KR101751394B1 - Device and Method for Scanning Printed Circuit Board - Google Patents

Abstract

There is provided an apparatus and a method for performing high-speed inspection of both sides of a printed circuit board. The apparatus for inspecting both sides of a printed circuit board includes a first carrier for sucking and fixing a lower surface of a printed circuit board to transfer the printed circuit board in one direction, a first camera for photographing an upper surface of the printed circuit board, A second carrier for vertically opening a part of a top surface of the printed circuit board to be separated from the first carrier and then conveying the first carrier in one direction, A second camera for photographing the lower surface, a second illumination for illuminating the lower surface of the printed circuit board, and a transmission illumination for illuminating the printed circuit board, wherein the first carrier and the second carrier are reciprocating .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printed circuit board

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical inspection apparatus, and more particularly, to an apparatus and a method for performing inspection on both sides of a printed circuit board at a high speed.

Printed circuit boards (PCBs) are robust, inexpensive, and highly reliable, and are used extensively in related industries such as semiconductors, multimedia devices, communication devices, various electronic products, and automobiles.

A manufacturing process of a printed circuit board is briefly described by exposing a surface of a photosensitive resin film to a photosensitive pattern using a wiring pattern film using a laminated board made of copper laminated inside and outside and etching the copper into a desired pattern using the characteristics of the photosensitive resin Thereby forming a wiring pattern. Thereafter, the pattern side and the insulating layer are laminated by using a press machine, holes are formed for electrical connection between the pattern layers, and then the holes are plated to electrically connect the laminated layers. Then, it is covered with wiring parts etc. by using photo solder resist (PSR) to prevent copper from being oxidized by contact with air or to prevent copper from being crushed by external shock or to prevent shorting due to metal.

Thereafter, a step of inspecting the printed circuit board is required. This is a step of inspecting various bonds such as the interval between fine line widths of the circuit pattern, short circuit to the circuit pattern, short circuit, protrusion, denting, foreign matter adhesion, appearance of the solder resist, .

That is, it is necessary to grasp the existence of the defective printed circuit board and filter it. At this time, effective inspection of the printed circuit board is a key to improving the quality and productivity, and accordingly, an optical inspection technique through camera photographing is used. As an item for inspecting the defects of the printed circuit board, a PSR part inspection for photographing the photo solder resist on the printed circuit board and inspecting whether or not the photo solder resist is properly applied on the circuit pattern which does not require solder, A plating section for inspecting whether or not the plating section formed in the hole is properly formed for electrically connecting between the printed circuit board layers, and inspecting the positions of the holes formed on the printed circuit board There is a penetration test. On the other hand, when wiring or the like is formed on both sides of the printed circuit board, the tests should be performed on both sides.

A problem to be solved by the present invention is to provide a printed circuit board which performs the PSR inspection, the plating inspection and the penetration inspection in one process as well as in a case where both sides of the printed circuit board are inspected, And an inspection apparatus and method.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided an apparatus for inspecting a printed circuit board, comprising: a first carrying unit for sucking and fixing a lower surface of a printed circuit board to transfer the printed circuit board in one direction; A first camera for illuminating an upper surface of the printed circuit board, a first illuminator for illuminating an upper surface of the printed circuit board, and a second illuminator for illuminating the upper surface of the printed circuit board, A second camera for photographing the lower surface of the printed circuit board, a second illumination for illuminating a lower surface of the printed circuit board, and a transmission illumination for illuminating the printed circuit board, And the second carrier can reciprocate.

According to another aspect of the present invention, there is provided a method of inspecting a printed circuit board, comprising the steps of: transferring the printed circuit board in one direction by sucking and fixing a lower surface of the printed circuit board to a first carrying unit; A step of picking up a part of the upper surface of the printed circuit board, separating the upper part of the printed circuit board from the first carrying part, and transferring the separated part in one direction And irradiating the lower surface of the printed circuit board with a second illumination and photographing the second camera with the second camera, wherein the first carrying unit and the second carrying unit are reciprocally moved in the one direction and the reciprocating motion in the reverse direction of the one direction can do.

Other specific details of the invention are included in the detailed description and drawings.

By performing the PPSR inspection, the plating inspection and the penetration inspection on the both sides of the printed circuit board in one step in a single process through the apparatus and method for inspecting the printed circuit board according to the present invention, .

1 is a schematic view of a printed circuit board inspection apparatus according to the present invention.
FIG. 2 is a side view showing a state in which a printed circuit board inspection apparatus according to the present invention collectively performs a PSR inspection, a plating inspection, and a penetration inspection on both sides of a printed circuit board.
3 is an embodiment showing a layout of a first camera, a first light, and a third light for inspecting an upper surface of a printed circuit board.
4 is a view showing an arrangement of a second camera, a second illumination, and a second carrier for inspecting a lower surface of a printed circuit board.
5 is a side cross-sectional view of a printed circuit board according to the present invention.
6 is a cross-sectional view showing the hemispherical structure of the third illumination and the fourth illumination.
7 is a flowchart for performing a method of inspecting a printed circuit board according to the present invention.
8 is a flowchart for performing a method of inspecting an upper surface of a printed circuit board.
9 is a flowchart for performing a method of inspecting a lower surface of a printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

One element is referred to as being "connected to " or" coupled to "another element, either directly connected or coupled to another element, One case. On the other hand, when one element is referred to as being "directly connected to" or "directly coupled to " another element, it does not intervene another element in the middle. Like reference numerals refer to like elements throughout the specification. "And / or" include each and every combination of one or more of the mentioned items.

Although the first, second, etc. are used to describe various elements, components and / or sections, it is needless to say that these elements, components and / or sections are not limited by these terms. These terms are only used to distinguish one element, element or section from another element, element or section. Therefore, it goes without saying that the first element, the first element or the first section mentioned below may be the second element, the second element or the second section within the technical spirit of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, embodiments of the present invention will mainly focus on inspection of both sides of a printed circuit board. However, it is apparent to those skilled in the art that the present invention can be applied to an inspection object requiring optical inspection on both sides as a plate form other than a printed circuit board.

FIG. 1 is a schematic view of a printed circuit board inspecting apparatus according to the present invention. FIG. 2 is a schematic view of a printed circuit board inspecting apparatus of the present invention collectively performing PSR inspection, plating inspection and penetration inspection on both sides of a printed circuit board FIG. FIG. 3 is an embodiment showing an arrangement of a first camera, a first light and a third light for inspecting an upper surface of a printed circuit board, FIG. 4 is a second camera for inspecting a lower surface of the printed circuit board, Illumination, and arrangement of the second carrier.

1, the printed circuit board inspection apparatus according to the present invention includes a first conveying unit 60, a first camera 10, a first light 20, a second conveying unit 70, (30), and a second illumination (40). The first conveyor 60, the first camera 10 and the first light 20 on the right side of FIG. 1 are photo solder resistors (PSR) on the upper surface of the double-sided printed circuit board 1 to be inspected, Sub-inspection, and plating inspection. The second conveying unit 70, the second camera 30 and the second lighting unit 40 on the left side of FIG. 1 perform a PSR inspection and a plating inspection on the lower surface of the double-sided printed circuit board 1 . In addition, the transmission illumination 80 on the left side of FIG. 1 above the second transportation part serves to illuminate the illumination when the transmission inspection is performed.

A printed circuit board inspection apparatus according to the present invention will now be described in detail with reference to FIGS. 1 and 2. FIG. The printed circuit board 1 to be inspected is placed on the first carrying portion 60 shown in Figs. 1 and 2. Although not shown in FIG. 1, a large number of fine holes passing through the first conveying unit 60 are formed, and a vacuum pump for sucking air through the holes at the lower end of the first conveying unit 60 is formed, The circuit board 1 is fixed so as not to move in close contact with the surface of the first carrying part. In particular, this close fixation is also necessary for focusing when taking a picture with a high magnification lens for inspection.

The first carrying portion 60 can move in one direction, and the first carrying portion 60 can move through the linear motion device 53 as shown in Fig. That is, the linear motion device moves at the same speed and direction as the moving speed and direction. The linear motion apparatus is formed with a long rod formed in the same direction as the one direction in which the first transportation section moves, and the first transportation section 60 is connected to the rod and moves along the rod. Since the linear motion apparatus can move both forward and backward, the first conveyance unit can also reciprocate in the arrow direction shown in FIG.

As shown in FIGS. 1 to 3, the first camera 10 is for displaying the upper surface of the printed circuit board. In the first camera shown in the drawings of the present invention, the two cameras 11 and 13 are illustrated. However, But is not limited thereto. A first illumination (20) is positioned between the first camera and the printed circuit board. The first illumination can also be determined corresponding to the number of cameras. The first camera in the present invention can be moved up and down to focus for shooting.

The first illumination 20 may illuminate different types of illumination depending on the item to be inspected. For example, each of the first lights 21 and 23 irradiates light having a frequency and a light amount suitable for the PSR part inspection and the plating part inspection, respectively, on the upper surface of the printed circuit board. That is, the first illumination in the present invention is not limited to the use of a plurality of lights having different colors and brightness, but may be applied to the photographing of the state of the printed circuit board on which the brightness and frequency of light are to be inspected in each illumination So that it is possible to irradiate the most suitably adjusted light according to the user's intention. When performing the PSR inspection and the plating inspection, it is necessary to irradiate different types of illumination because each illumination is reflected from the surface of the printed circuit board or light is absorbed This is because the types of illumination for making the optimum photo solder resist section photography and the optimum plating section photography are different from each other.

The first carrying part reciprocates in a horizontal direction and moves. 2, the PSR part inspection is performed while moving the printed circuit board once fixed to the first carrying part, as shown in FIG. 2. The first illumination irradiates the illumination suitable for the inspection of the PSR part, The first camera photographs the upper surface of the printed circuit board. The first conveying unit is horizontally moved backward (the rightward direction in FIG. 2) to perform inspection of the plating unit, which is an inspection item, and the first illumination extinguishes the illumination suitable for the inspection of the PSR unit. Then, the first carrying unit performs the inspection of the plating unit while moving to the left again, wherein the first illumination irradiates the illumination suitable for the inspection of the plating unit, and in this state, the first camera photographs the upper surface of the printed circuit board. Each time the first carrying part moves in a specific direction, a different kind of inspection is performed.

Here, the illumination suitable for the inspection of the PSR part and the illumination suitable for the inspection of the plating part are distinguished because the PSR part and the plating part are formed in different colors, so if the same type of illumination is irradiated, I can not do it. That is, the frequency and light amount of light for bringing out an optimal image when photographing the PSR part and the frequency and light amount of light for bringing out an optimal image at the time of photographing are different from each other. The first illumination and the second illumination according to the present invention do not irradiate the fixed frequency and the light amount but the optimal image is obtained even if the type of the PCB to be inspected changes or the color of the PSR part and the plating part of the PCB to be inspected change, The frequency and light quantity of the light can be changed so that it can be photographed.

In the above description, the plating unit inspection is performed after the execution of the PSR inspection. However, the inspection sequence may be changed and the shooting is performed only in a specific direction (left direction in FIG. 2) It may be possible to perform another kind of inspection while moving in the opposite direction of the one direction.

Shooting is carried out while the first conveying part is moving, in which a transparent tube 51 as seen in Figs. 2 and 3 can be used to fix the lights. Glass, and plastic, so that the first conveying unit and the printed circuit board to be inspected are moved.

When the inspection of the PSR part and the inspection of the plating part on the upper surface of the printed circuit board are completed through the reciprocating motion, the first carrying part moves further in the leftward direction of FIG. 2 to transfer the printed circuit board to the second carrying part 70 do.

Next, a process of performing a PSR inspection, a plating inspection and a penetration inspection on the lower surface of the printed circuit board will be described with reference to FIGS. 1, 2, 4, and 5. FIG. The left side of Fig. 1 is a schematic view for performing inspection on the lower surface of the printed circuit board, and the second carrier can be moved in one direction, similarly to the direction of the indicated arrow.

In FIG. 4, the shape of the second conveying unit 70 is schematically shown, but the method of fixing the printed circuit board to the second conveying unit is also performed through adsorption of air. However, in an embodiment of the present invention, the second conveying portion takes a form different from that of the first conveying portion. 4, two long plate shapes are formed parallel to each other, and at the point between the two second plate-shaped carriers, transmission light So that the upper surface of the printed circuit board can be irradiated. Since the shape is different from that of the first carrying part, the vacuum bump for sucking the printed circuit board to be inspected through the suction pressure of air is not formed on the entire surface like the first carrying part, Lt; / RTI > long plates. Meanwhile, the second conveying unit 70 is configured such that two long plates are parallel to each other, and the interval between the two plates is adjustable according to the width of the printed circuit board to be inspected.

In this specification, the shape of the second carrier is described as two long plates. However, the shape of the second carrier is not limited to this, and if the printed circuit board can be sucked from above, There will be no.

In FIG. 2, the printed circuit board 1 having passed through the transparent tube after having been inspected for the upper surface thereof is lifted by the second conveying portion only on both sides of the printed circuit board by the air adsorption method. At this time, Thereby stopping the operation of the vacuum pump for sucking air through the holes at the lower end of the first conveying portion 60 so that the printed circuit board is separated from the first conveying portion by the second conveying portion. Thereafter, the printed circuit board, which is attracted to the second conveying portion, is moved to the position of the second camera 30 and the second light 40.

1, 2, and 4, the second conveying unit reciprocates left and right at the top of the second camera 30 and the second illumination unit 40, Perform the inspection. 5 is a side cross-sectional view of a printed circuit board inspection apparatus according to the present invention. The second carrying part can move not only in the left and right direction but also in the vertical direction, thereby contributing to the focusing of the second camera 30.

The PSR sub-inspection and the plating sub-inspection are performed twice, and the method of performing the inspection of the lower surface of the printed circuit board is performed in a manner similar to that of performing inspection on the upper surface of the printed circuit board. That is, when the printed circuit board sucked and fixed to the second conveying unit is moved to the left, the second illumination is illuminated and the photographing is carried out for the inspection of the PSR unit. Thereafter, when moving again in the reverse direction (the rightward direction in FIG. 2) and moving again to the left side, the second illumination is switched to the illumination for inspection of the plating section and the photographing is performed.

When the PSR sub-inspection and the plating sub-inspection are completed, the second illumination is extinguished, the transmission illumination 80 shown in Fig. 1 or 4 is turned on, and the second conveying unit reverses the printed circuit board And a transmission inspection is performed to capture the holes formed in the printed circuit board by the second camera. After the photographing for the transmission inspection is completed, the second carrier moves the printed circuit board 1 from the upper portion of the second camera 30 and the second light 40 to another place, The PSR sub-inspection, the plating inspection, and the penetration inspection are completed.

Various methods are used for checking the printed circuit board to improve the accuracy. That is, not only a very precise CCD image pick-up is required but also a case where a defective printed circuit board is erroneously judged as a defect by shading formed by a shape such as a circuit pattern formed on a printed circuit board is prevented There is a need.

In general, in the case of a printed circuit board, one side may have a more complicated structure than the other side. In this case, the accuracy of the inspection can be improved by more precise photographing of the side having a complicated configuration. As shown in FIG. 3, the first camera and the first illumination may be formed in two, respectively. As shown in FIG. 3, the two cameras 11 and 13 are arranged to be offset from each other, It is possible to increase the precision within the processing capacity that each camera can accommodate.

It is also possible to further add a method of diversifying the directions of the light sources irradiated toward the printed circuit board in order to prevent inspection errors due to the shape formed on the printed circuit board. The third illuminations 101 and 103 and the fourth illuminator 105 shown in FIG. 2 perform this function. The third illuminator and the fourth illuminator each have an error of inspection on the upper and lower surfaces of the printed circuit board, respectively Which are added to prevent light. The third illumination is positioned between the first illumination and the printed circuit board, and the fourth illumination is positioned between the second illumination and the printed circuit board to illuminate the printed circuit board. The third illumination and the fourth illumination can have the same structure, and the concrete form thereof is the same as that of FIG. A plurality of light sources 113 and 115 are arranged on the side surface of the hemisphere toward the inner side of the hemisphere so that the light sources reach the one side of the printed circuit board at various angles, And irradiates light toward the inner side of the light guide plate. The light reflected from the inner side reaches the one surface of the printed circuit board at various angles, so that there is no shade due to the shape formed on the printed circuit board, thereby preventing errors in the inspection.

FIG. 7 is a flowchart for performing a method of inspecting a printed circuit board according to the present invention, and FIGS. 8 and 9 are flowcharts for performing a method of inspecting a top surface and a bottom surface of a printed circuit board, respectively.

The lower surface of the printed circuit board is sucked and fixed to the first carrying part of the present invention to transfer the printed circuit board in one direction. The upper surface of the printed circuit board is photographed in the process of moving in the one direction to perform inspection. Inspection of the upper surface of the printed circuit board is carried out by photographing the photo solder resist on the printed circuit board and inspecting whether the photo solder resist is properly coated on the circuit pattern which does not require solder and the plating part on the printed circuit board Thereby performing a plating portion inspection for checking whether or not the plating portion formed on the printed circuit board is properly formed. If the PSR sub-inspection is performed first, the first illumination examines the illumination suitable for the PSR sub-inspection. When the first carrying part moves in one direction, the photo-solder resist on the upper surface of the printed circuit board is photographed to acquire data. Then, the first illumination is changed by adjusting the frequency or brightness of the light so as to be suitable for inspection of the plating part. When the first carrying unit moves in the one direction, the plating unit on the upper surface of the printed circuit board is photographed to acquire data.

When the inspection of the PSR portion and the inspection of the plating portion on the upper surface of the printed circuit board are completed, the second horizontal operation portion sucks and separates the printed circuit board to separate the printed circuit board from the first carrying portion. And the second carrier horizontally moves the separated printed circuit board to the upper portion of the second camera and the second illumination, the second camera and the second illumination perform inspection of the lower surface of the printed circuit board.

At this time, similarly, the PSR part inspection and the plating part inspection are performed, and a part of the upper surface of the printed circuit board is sucked and fixed to the second conveying part to transfer the printed circuit board in one direction. The lower surface of the printed circuit board is photographed in the process of moving in one direction to perform inspection. In this case, each time the inspection is performed, the light irradiated in the second illumination is changed by adjusting the frequency or brightness of the light so as to be suitable for each inspection.

When the inspection of the PSR part and the plating part is completed, the second illumination is turned off and the transmission illumination is illuminated downward from the upper part of the printed circuit board, and the holes formed on the printed circuit board are photographed to inspect the position of the holes . When the transmission inspection is completed, the second carrier moves the printed circuit board to another position.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1: Printed circuit board to be inspected
10, 11, 13: First camera
20: First light
30: Second camera
40: Second lighting 51: Transparent tube
60: first conveying portion 70: second conveying portion
80: Transmitted illumination 101, 103: Third illumination
105: Fourth illumination

Claims (15)

A first transport unit for sucking and fixing a lower surface of a printed circuit board to transfer the printed circuit board in one direction;
A first camera for photographing an upper surface of the printed circuit board;
A first illumination for illuminating an upper surface of the printed circuit board;
A second transporting unit configured to vertically open the first transporting unit, the second transporting unit separating a portion of the upper surface of the printed circuit board from the first transporting unit, and then transporting the first transporting unit in the one direction;
A second camera for photographing the lower surface of the printed circuit board;
A second illumination unit for illuminating a lower surface of the printed circuit board; And
And transmission illumination for illuminating the printed circuit board,
Wherein the first conveying portion and the second conveying portion reciprocate. The method according to claim 1,
Wherein the first carrying part performs the one-directional movement through the reciprocating motion a plurality of times, and the first carrying part photographs the photo solder resist part on the upper surface of the printed circuit board when the first carrying part moves in the one direction, And wherein the controller is configured to photograph the plating unit on the upper surface of the printed circuit board during the second movement in the one direction. The method according to claim 1,
Wherein the second carrying portion performs the one-directional movement through the reciprocating motion a plurality of times, the second carrying portion photographs the photo solder resist portion on the lower surface of the printed circuit board when the first carrying portion moves in the one direction, Wherein the second transporting unit photographs a hole formed on the printed circuit board when the second transporting unit is moved to the third direction in the one direction. 3. The method of claim 2,
Wherein the first camera irradiates the photo-solder resist portion on the upper surface of the printed circuit board with the light illuminated by the first illuminator and the light illuminated by the first illuminator when the first camera photographs the plating portion on the upper surface of the printed circuit board Is a device for inspecting both sides of printed circuit boards differing in frequency or amount of light. The method of claim 3,
Wherein the first camera illuminates the photo solder resist portion on the lower surface of the printed circuit board by the second camera and the second camera illuminates the second illuminated portion when the second camera photographs the plating portion on the lower surface of the printed circuit board Is a device for inspecting both sides of printed circuit boards differing in frequency or amount of light. The method according to claim 1,
Wherein the first camera is divided into a plurality of groups, and the plurality of first cameras divides the area of the upper surface of the printed circuit board by the number of the first cameras. The method according to claim 1,
A third illumination which is positioned between the first illumination and the printed circuit board to illuminate an upper surface of the printed circuit board, or a third illumination which illuminates the lower surface of the printed circuit board between the second illumination and the printed circuit board Further comprising a fourth illumination, wherein the third illumination and the fourth illumination each have a hemispherical reflector on the inner side and one or more light sources for illuminating the inner side of the reflector to illuminate light to be reflected to the printed circuit board And a printed circuit board. Transferring the printed circuit board in one direction by sucking and fixing the lower surface of the printed circuit board to the first carrying unit;
Illuminating an upper surface of the printed circuit board with a first illumination and photographing the first camera with the first illumination;
A second transporting unit having a vertically opened structure for sucking a part of a top surface of the printed circuit board, separating the upper surface of the printed circuit board from the first transporting unit, And
Illuminating the lower surface of the printed circuit board with a second illumination and photographing with the second camera,
Wherein the first carrying portion and the second carrying portion reciprocate a plurality of times in the one direction and the opposite direction of the one direction. 9. The method of claim 8,
Further comprising the step of photographing a hole of the printed circuit board with the second camera by illuminating the printed circuit board with transmission light after illuminating with the second illumination. 9. The method of claim 8,
Wherein the first carrying part performs the one-directional movement through the reciprocating motion a plurality of times, and the first carrying part photographs the photo solder resist part on the upper surface of the printed circuit board when the first carrying part moves in the one direction, And the plating section on the upper surface of the printed circuit board is photographed when the second movement in the one direction is performed. 9. The method of claim 8,
Wherein the second carrying portion performs the one-directional movement through the reciprocating motion a plurality of times, the second carrying portion photographs the photo solder resist portion on the lower surface of the printed circuit board when the first carrying portion moves in the one direction, Wherein the second transporting unit photographs a hole formed on the printed circuit board when the second transporting unit moves to the third direction in the one direction. 11. The method of claim 10,
Wherein the first camera irradiates the photo-solder resist portion on the upper surface of the printed circuit board with the light illuminated by the first illuminator and the light illuminated by the first illuminator when the first camera photographs the plating portion on the upper surface of the printed circuit board A method for inspecting two-sided printed circuit boards different in frequency or amount of light. 12. The method of claim 11,
Wherein the first camera illuminates the photo solder resist portion on the lower surface of the printed circuit board by the second camera and the second camera illuminates the second illuminated portion when the second camera photographs the plating portion on the lower surface of the printed circuit board A method for inspecting two-sided printed circuit boards different in frequency or amount of light. 9. The method of claim 8,
Wherein the first camera is divided into a plurality of groups, and the plurality of first cameras divides the area of the upper surface of the printed circuit board by the number of the first cameras. 9. The method of claim 8,
A third illumination which is positioned between the first illumination and the printed circuit board to illuminate an upper surface of the printed circuit board, or a third illumination which illuminates the lower surface of the printed circuit board between the second illumination and the printed circuit board Further comprising a fourth illumination, wherein the third illumination and the fourth illumination each comprise at least one light source having a hemispherical reflector and an inner surface of the reflector to shoot light to be reflected to the printed circuit board A method of inspecting a printed circuit board on both sides.

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