JP3665495B2 - Inspection device and method for cream solder printing machine and printing machine having the inspection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection apparatus and method for inspecting the shape and the like of cream solder printed by a printing machine that prints cream solder on a printed circuit board on which electronic components are mounted, and a printing machine having the inspection apparatus.
[0002]
[Prior art]
In recent years, in the mounting method of electronic components, inspection after cream solder printing has become increasingly important due to the appearance of new devices such as CSP (Chip Size Package). Under such circumstances, high-performance inspection of the printed state of cream solder has become an important part in determining the quality of the final product.
Hereinafter, an example of the above-described conventional inspection apparatus will be described with reference to the drawings. FIG. 5 is a diagram showing a configuration of a conventional apparatus for inspecting cream solder printed on a printed circuit board. The printed circuit board 32 on which the cream solder 31 is printed is picked up by the black and white camera 34, the window frame portion of the part to be inspected is set with respect to the image by the video signal, and the image in the window frame portion is analyzed to analyze the cream solder 31. Check the print status.
[0003]
That is, the monochrome camera 34 is disposed above the printed circuit board 32 on which the cream solder 31 is printed, and the illumination 35 is disposed on both sides thereof, and the printed circuit board 32 is imaged by the monochrome camera 34. The video signal transmitted from the black and white camera 34 is binarized in comparison with the binarized data of the cream solder 31 set in advance by the binarization processing unit 36. Next, the calculation unit 37 obtains the area and the center of gravity of the cream solder 31 based on the binarized information of the cream solder 31, and determines a predetermined determination reference area and determination reference position deviation amount. 38, the quality of the cream solder printing state was determined. In FIG. 5, 33 is a land of the printed circuit board 32, and 39 is a wiring pattern of the printed circuit board 32.
[0004]
[Problems to be solved by the invention]
However, the conventional device for inspecting cream solder after printing by a black and white camera may have the same brightness level of cream solder and the brightness level of the background. In many cases, the cream solder cannot be inspected normally. In addition, the color image processing method and the three-dimensional measurement make the device itself expensive and make it difficult to install the equipment.
[0005]
Further, in the conventional optical system, accurate area measurement is difficult due to irregular reflection of irradiation light caused by flux on the surface of the cream solder and variations in reflected light due to the shape of the printed cream solder.
[0006]
Further, in the conventional optical system, illumination close to epi-illumination is necessary for identifying feature patterns on a printed circuit board for positioning, and diffuse illumination from all directions is necessary for identifying cream solder. It was difficult to achieve both types of discrimination with an optical system.
The present invention solves the above-described problem, and in an inspection apparatus for imaging a printed circuit board on which cream solder is printed, an inspection apparatus for a cream solder printer that can accurately and accurately inspect printed cream solder. And a method and a printing machine having the inspection apparatus.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is configured as follows.
[0008]
According to the first aspect of the present invention, in the inspection apparatus for inspecting the cream solder printed by the printing machine for printing the paste-like cream solder on the substrate by the imaging device,
A green wavelength removing member that removes only the green wavelength among the wavelengths incident on the imaging device;
An illuminating device having an omnidirectional illumination device that illuminates the side surface of the cream solder omnidirectionally from a direction different from the height direction of the solder, and an epi-illumination device that illuminates a planar pattern on the substrate;
A control device that switches the omnidirectional illumination device and the epi-illumination device according to the object to be illuminated,
When the object to be imaged is a planar pattern on the substrate by the control device, the epi-illumination device is turned on and the omnidirectional illumination device is turned off, while the object to be imaged is the solder on the substrate. In this case, a cream solder inspection apparatus is provided in which the omnidirectional illumination device is turned on and the epi-illumination device is turned off.
[0009]
According to the second aspect of the present invention, the apparatus further comprises a data storage unit that holds data for specifying an object to be imaged,
A first mode of controlling the epi-illumination device and the omnidirectional illumination device to be turned on or off by analyzing the data specifying the object to be imaged, which is held in the data storage unit, with the control device The cream solder test | inspection apparatus as described in is provided.
[0013]
According to the 3rd aspect of this invention, the cream solder printer which has the said cream solder test | inspection apparatus of the 1st or 2nd aspect is provided.
[0014]
According to the fourth aspect of the present invention, in the inspection method for inspecting the cream solder printed by the printing machine for printing the paste-like cream solder on the substrate with the imaging device,
When the cream solder is imaged by the imaging device, all the side surfaces of the cream solder are omnidirectionally illuminated from a direction different from the height direction of the solder with an omnidirectional illumination device of one illumination device, The incident light enters the imaging device while controlling the illumination device to be switched in accordance with the object to be illuminated so that the epi-illumination device of the one illumination device illuminates the positioning pattern on the substrate. Provided is a cream solder inspection method characterized by removing only a green wavelength out of wavelengths.
[0016]
According to the fifth aspect of the present invention, data specifying an object to be imaged is held in a data storage unit, and data specifying the object to be imaged held in the data storage unit is analyzed by the control device. Then, the cream solder inspection method according to the fourth aspect of controlling the epi-illumination device and the omnidirectional illumination device to be turned on or off is provided.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, various embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a cream solder inspection apparatus according to a first embodiment of the present invention.
In FIG. 1, 1 is a printed circuit board, 2 is cream solder printed on the printed circuit board 1, 4 is a land on the printed circuit board 1, and 5 is a wiring pattern on the printed circuit board 1. Also, 6 is a monochrome camera, 7 is a filter for removing a green component, 8 is a lighting device, and 9 is a portion that receives a video signal captured by the monochrome camera 6 and indicates the brightness of the cream solder 2 set in advance. It is a binarization processing unit that extracts and binarizes. Reference numeral 10 denotes a calculation unit that measures the area and size of the solder extracted by the binarization processing unit 9 by calculation. Reference numeral 11 denotes a determination unit that determines the quality of solder printing based on a preset threshold value. .
[0020]
FIG. 2 shows that the portion of the substrate on which the solder is not printed (including the portion other than the portion on which the solder is printed) is green because of the resist applied to the substrate. Since the brightness of the solder is almost the same as that of the solder, the operation of the filter 7 for removing the green color will be described. FIG. 2A is a characteristic diagram of the filter 7 in which the vertical axis indicates the transmittance and the horizontal axis indicates the wavelength. FIG. 2B is a diagram showing the effect of the filter 7. That is, when passing through the filter 7, it can be seen that blue or red light is transmitted 80% or more, but only green is not transmitted. In FIG. 2B, a portion surrounded by a dotted line is an area indicating the brightness of the solder.
[0021]
FIG. 3 is a diagram illustrating a configuration of the illumination device 8. 12 is an illumination device for irradiating the cream solder 2 from all directions around it, 13 is an epi-illumination device for identifying a feature pattern on the printed circuit board 1, and 14 is a control unit for switching the illumination device 12. Reference numeral 15 denotes a data storage unit having data for specifying an object to be imaged. With this configuration, according to the object, specifically, when illuminating the solder, the control unit 14 illuminates only the omnidirectional illumination device 12 to perform omnidirectional illumination. In order to illuminate the pattern, the planar illumination pattern can be illuminated by the epi-illumination device 13 by turning off the omnidirectional illumination device 12 and turning on the epi-illumination device 13 by the control unit 14.
[0022]
FIG. 4 explains the relationship between cream solder shape and area measurement, as will be described later.
[0023]
Hereinafter, the operation of the above-described cream solder inspection apparatus will be described with reference to FIGS.
A printed circuit board 1 as an example of an object to be inspected is imaged by a monochrome camera 6. At this time, when the incident light passes through the filter 7, as shown in FIG. 2B, the green color indicating the portion of the printed board 1 where the solder is not printed is removed, and the brightness level is reduced. As a result, a difference occurs in the brightness level between the wiring pattern 5 on the substrate 1 and the cream solder 2. After passing through the filter 7k, the cream solder 2 is binarized by the binarization processing unit 9, and the area and position of the solder 2 are measured by the calculation unit 9 based on the binarized information. It is determined whether the solder printing is good or bad by determining whether the area or position is within an allowable range.
[0024]
Next, when the cream solder 2 is imaged, an illumination device 8 that irradiates the entire cream solder 2 is used, so that an ideal shape (for example, FIG. 4b) is obtained as shown in FIGS. As shown in FIGS. 4 (a) and 4 (d), the cream solder 2 which is not a shape having a small slope of the solder slope as shown in FIG. As shown in (c) and (f), an accurate two-dimensional image can be obtained. That is, in this embodiment, when the reflected light source illuminates the solder 2 downward from above the solder 2, the light beam reflected by the surface of the solder 2 enters the monochrome camera 6 above the solder 2, Imaging is performed. Therefore, as shown in FIG. 4B, when the side surface of the solder 2 has almost no inclination, and the illumination light is illuminated downward from above the solder 2, most of the reflected light from the solder 2 enters the camera. In the ideally shaped solder 2, as shown in FIG. 4E, the portion that cannot be measured in the solder 2 is a very small area around the solder 2, and most of the solder 2 can be measured.
[0025]
On the other hand, as shown in FIG. 4A, when the side surface of the solder 2 has a gentle inclination, the reflected light beam from the incident light source reflected by the side surface of the solder 2 does not enter the monochrome camera 6. For this reason, as shown in FIG. 4D, the side surface portion other than the flat surface of the central portion of the solder 2 becomes a non-measurable region, and the accurate area and position of the solder 2 cannot be measured. On the other hand, in the present embodiment, as shown in FIG. 4C, not the simple incident light source but the side surface of the solder 2 can be illuminated from the side surface side of the solder 2. The reflected light beam reflected from the side surface of the black and white can enter the black and white camera 6, and as shown in FIG. 4 (f), almost the region of the side surface of the solder 2 can be measured.
[0026]
Here, the control configuration of the illumination device 8 will be described with reference to FIG. The data stored in the data storage unit 15 is analyzed by the control unit 14 for driving the illumination device, and the target of imaging is a feature pattern on the printed circuit board 1 (for example, a positioning pattern used for positioning such as a mark). In this case, the epi-illumination device 13 that is a component of the illumination device 8 is turned on, and the omnidirectional illumination device 12 is turned off. In addition, when the object to be imaged is the cream solder 2 on the printed circuit board 1, the omnidirectional illumination device 12 is turned on and the epi-illumination device 13 is turned off. As a result, the amount of light that falls perpendicular to the plane can be reduced. As a result, a better contrast can be obtained in the case of feature pattern identification, and an area measurement error due to flux reflection or the like can be reduced in the case of solder inspection.
[0027]
According to the said embodiment, there can exist the following effects.
First, when the cream solder 2 printed on the printed circuit board 1 is illuminated and imaged, a difference in brightness level between the solder 2 and the green portion on the printed circuit board 1 occurs, which is difficult in conventional monochrome image processing. It was. However, in this embodiment, by removing the green wavelength with the filter 7, the difference in brightness between the cream solder 2 on the printed circuit board and the pattern on the green printed circuit board 1 is increased. Can be accurately distinguished, whereby the cream solder 2 can be accurately inspected.
[0028]
Furthermore, even when the shape of the cream solder 2 is not correct, the inspection can be performed accurately.
Furthermore, it is possible to achieve both the identification of the feature pattern on the printed circuit board 1 and the inspection of the cream solder with the same optical system.
[0029]
【The invention's effect】
As described above, it is impossible to accurately distinguish the pattern on the printed circuit board that is green and the cream solder on the conventional printed circuit board by cutting the green component among the components of the light rays incident on the imaging device. The problem that was possible can be solved, and the cream solder can be inspected accurately.
[0030]
Furthermore, by applying light from all directions to cream solder that is printed without using a single-direction light source for the solder, it is affected by the reflection of the flux contained in the cream solder and the shape of the cream solder. And accurate inspection.
Furthermore, by combining the omnidirectional illumination and the epi-illumination, the identification of the feature pattern on the printed circuit board and the inspection of the cream solder can be made compatible by selecting and inspecting the optimum illumination respectively.
Further, by switching the omnidirectional illumination from all directions for the epi-illumination and the cream solder according to the object to be imaged, it is possible to perform more accurate feature pattern identification and cream solder inspection.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a configuration of a cream solder printing inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating the operation of a filter that removes green only in FIG. 1;
FIG. 3 is a diagram showing a configuration of the illumination device of FIG. 1;
FIG. 4 is a diagram showing the relationship between cream solder shape and area measurement.
FIG. 5 is a diagram showing a configuration of a conventional cream solder printing inspection apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Cream solder 4 Land 5 Wiring pattern 6 Black-and-white camera 7 Filter 8 Illumination device 9 Binarization processing part 10 Arithmetic part 11 Determination part 12 Omnidirectional illumination apparatus 13 Epi-illumination illumination apparatus 14 Control part 15 Data storage part

Claims (5)

In an inspection device that inspects cream solder printed by a printing machine that prints paste-like cream solder on a substrate with an imaging device,
A green wavelength removing member that removes only the green wavelength among the wavelengths incident on the imaging device;
An illuminating device having an omnidirectional illumination device that illuminates the side surface of the cream solder omnidirectionally from a direction different from the height direction of the solder, and an epi-illumination device that illuminates a planar pattern on the substrate;
A control device that switches the omnidirectional illumination device and the epi-illumination device according to the object to be illuminated,
When the object to be imaged is a planar pattern on the substrate by the control device, the epi-illumination device is turned on and the omnidirectional illumination device is turned off, while the object to be imaged is the solder on the substrate. In this case, the omnidirectional illumination device is turned on and the epi-illumination device is turned off. A data storage unit that holds data for specifying an object to be imaged;
The data for specifying the object to be imaged, which is stored in the data storage unit, is analyzed by the control device, and the epi-illumination device and the omnidirectional illumination device are controlled to be turned on or off. Cream solder inspection apparatus as described in 1.   A cream solder printing machine having the cream solder inspection apparatus according to claim 1. In an inspection method for inspecting cream solder printed by a printing machine that prints paste-like cream solder on a substrate with an imaging device,
When the cream solder is imaged by the imaging device, all the side surfaces of the cream solder are omnidirectionally illuminated from a direction different from the height direction of the solder with an omnidirectional illumination device of one illumination device, The incident light enters the imaging device while controlling the illumination device to be switched in accordance with the object to be illuminated so that the epi-illumination device of the one illumination device illuminates the positioning pattern on the substrate. A cream solder inspection method, wherein only the green wavelength is removed from the wavelengths.   Data for specifying an object to be imaged is stored in a data storage unit, and data for specifying an object to be imaged that is stored in the data storage unit is analyzed by the control device, so that the epi-illumination device and the omnidirectional The cream solder inspection method according to claim 4, wherein the lighting device is controlled to be turned on or off.

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