JP4987511B2 - Inspection equipment for printed wiring boards - Google Patents

Description

  The present invention relates to an inspection apparatus for inspecting a defect of a wiring pattern by photographing a surface of a printed wiring board having a silk region on which ink is printed on a surface of a substrate body and a metal region having silver luster.

  2. Description of the Related Art A printed wiring board printed with an ink is widely used for explanation of components and the like mounted on a surface of a substrate body and a metal pattern. In the production of the printed wiring board, an inspection is performed for a defect in a wiring pattern or the like. As one of the defect inspection methods, for example, as disclosed in Patent Document 1, a method for optically inspecting a printed wiring board has been proposed.

  This method is a method in which a printed wiring board is imaged using a camera, a region such as a signal line, a power supply line, or a pad portion is divided from the obtained image, and a defect inspection of each region is performed.

In this method, each of the areas provided on the printed wiring board, that is, the division of each pattern area of the wiring pattern area, the resist area, the pad area, and the silk area has a different color due to the difference in the constituent materials. Focusing on this, a method of dividing the pattern area for each color component is adopted.
JP-A-11-304720

  However, the substrate is provided with a metallic region having silver luster such as a plated region in which the surface of the wiring print is plated with silver or a solder leveler. Since the silk print is usually printed using white ink, both the silk area and the metal area having silver gloss are captured in white in the image. Therefore, in the inspection method disclosed in Patent Document 1 in which the substrate is imaged using the camera, it is impossible to distinguish and inspect the metal area having silver luster, for example, both the solder leveler and the silk area. It was.

  For this reason, inspecting the metal area with silver luster on the printed wiring board is performed before the final plating process, or by dividing the area with reference to the design data instead of the manufactured substrate. It was broken. The former method cannot inspect the printed circuit board itself, which is the final product, and the latter method inspects without considering the manufacturing error between the design drawing and the actually manufactured product. Therefore, it is difficult to increase the accuracy of the inspection.

  Therefore, a technical problem to be solved by the present invention is to provide a printed wiring board inspection apparatus capable of optically distinguishing between ink printing and a metallic region having silver gloss.

  In order to solve the above technical problem, the present invention provides a printed wiring board inspection apparatus having the following configuration.

According to the first aspect of the present invention, a printed wiring board having a silver glossy metal area and a silk area on which ink printing has been performed is imaged on the surface of the substrate body, and is divided into a metal area, a silk area, and other areas. an inspection apparatus for to inspection,
A color camera arranged so that the surface of the printed wiring board can be imaged;
A white light source the irradiated with white diffused light at an angle of 30 to 60 degrees against the printed wiring board surface, is arranged so as to form a diffuse reflecting optical system and the color camera,
The colored light is emitted to the surface of the printed wiring board so that the illuminance is lower than the white light emitted from the white light source, and the regular reflection light of the colored light on the surface of the printed wiring board is directed to the color camera. A colored light source arranged at such a position as to enter,
Receiving image data of the printed wiring board imaged by the color camera, and recognizing the portion colored in the color of the colored light by the colored light source in the image data as the metal region, and separating the region from the silk region And a recognition inspection unit for inspecting the printed wiring board. A printed wiring board inspection apparatus is provided.

According to a second aspect of the present invention, the color camera is a linear sensor,
The colored light source is composed of a linear light source arranged to be parallel to the pixel array of the linear sensor,
The printed wiring board inspection apparatus according to the first aspect, further comprising a drive unit that moves the printed wiring board in a direction orthogonal to a pixel arrangement direction of the linear sensor with respect to the coloring light source and the linear sensor. I will provide a.

According to the onset bright, colored light emitted from the colored light source, you characterized in that illuminance than the white light emitted from the white light source is configured lower.

According to a third aspect of the present invention, there is provided the printed wiring board inspection apparatus according to any one of the first and second aspects , wherein the colored light is red light.

According to a fourth aspect of the present invention, there is provided the printed wiring board according to any one of the first to third aspects , wherein an incident angle of the colored light source is smaller than an incident angle of the white light source. Provide inspection equipment.

According to the fifth aspect of the present invention, the color camera arranged so that the surface of the printed wiring board can be imaged, and the colored light is emitted to the surface of the printed wiring board and the color light on the surface of the printed wiring board is corrected. a colored light source the reflected light is positioned such that incident to the color camera, a white diffuse light at an angle of 30 to 60 degrees against the printed circuit board surface illuminated, diffuse reflection and the color camera Using an inspection apparatus having a white light source arranged so as to constitute an optical system, a metal region having silver luster, a silk region, and a discriminable region visually distinguishable from the metal region and the silk region An inspection method for inspecting a printed wiring board having:
The first image obtained by capturing only the white light source and capturing the printed wiring board is captured,
The second image obtained by imaging the printed wiring board by turning on the white light source and the colored light source,
Based on the color information of each pixel displayed in the first image, it is possible to determine a region division between the distinguishable region and the other region including the metal region and the silk region ,
Provided is a printed wiring board inspection method, wherein region division between the metal region and the silk region is determined based on color information of each pixel displayed in the second image.

According to a sixth aspect of the present invention, the brightness of the white light emitted from the white light source is changed in the step of capturing the first image and the step of capturing the second image. A printed wiring board inspection method according to a fifth aspect is provided.

  According to the present invention, the colored light source and the color camera constitute a regular reflection optical system, and the white light source and the color camera constitute a reflection diffusion optical system. Therefore, the reflection / diffusion characteristics of colored light are different between the surface of the silk region whose surface is the diffusion surface and the surface of the metal region whose surface is the reflection surface. That is, in the metal region, the reflection component of the colored light source becomes stronger and becomes more dominant than white light. Therefore, the color camera picks up an image of the metal region as if colored by the color of the colored light as a result of the color of the light source itself being specularly reflected light becoming stronger, not the color of the subject itself. On the other hand, in the silk region, since the reflection component of the colored light source is not so strong compared to the diffuse component, white light from the white light source is dominant, so the color camera uses the color of the silk region itself (for example, white ). Therefore, on the image, the silk region and the metal region can be distinguished based on the color of the pixel, and both regions can be divided.

  In addition, by configuring the color camera and the colored light source in a linear shape, it becomes easier for only the regular reflection component of the colored light from the colored light source to enter the color camera, and a more accurate regular reflection optical system can be configured. .

  In addition, by reducing the illuminance of the colored light lower than that of the white light, the influence of the diffused light due to the white light becomes stronger, so the influence of the colored light is reduced in the imaging in the silk region, and the color difference is made clearer. Can do.

  By making the incident angle of the colored light source smaller than the incident angle of the white light source, the ratio of the reflected white light component from the white light source to the color camera can be reduced, and the printed wiring board is widened by the white light. The area can be illuminated.

  Hereinafter, a printed wiring board inspection apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of an appearance of a printed wiring board inspection apparatus according to an embodiment of the present invention. FIG. 2A is a schematic diagram showing a schematic configuration when attention is paid to the optical system of the printed wiring board inspection apparatus of FIG. The printed wiring board inspection apparatus 1 in FIG. 1 colors the mounting stage 2 on which the printed wiring board 100 to be inspected is mounted, the base 3 that supports the mounting stage so as to be movable, and the printed wiring board 100. A colored light source 4 that is a light source for irradiating light, a color camera 5 that receives specularly reflected light that is emitted from the colored light source 4 and reflected by the surface of the printed wiring board 100, and the surface of the printed wiring board is irradiated with white light to produce color. A white light source 6 arranged so as to constitute a diffuse reflection optical system with the camera 5, and a recognition inspection unit 7 for performing recognition and inspection of each area of the printed wiring board using image data captured by the color camera 5. And.

  Prior to the description of the apparatus, the configuration of the printed wiring board 100 to be inspected will be described. On the surface of the printed wiring board 100, there are formed a wiring pattern region, a resist region, a pad region, a silk region, a plated region obtained by applying silver plating to the surface of the substrate, and a metal region having silver luster such as a solder leveler. Has been. In addition, the metal area | region is comprised by the mirror surface which has silver luster. The silk region is provided with a description of a chip mounted on a printed wiring board by printing, and usually white ink is used. Since the silk region is composed of printing ink, the surface is a diffusion surface.

  Each of these regions has a different color visually due to a difference in constituent materials. However, if the mirror area is made of silver gloss, the silk area printed with white ink will be visually different, but if it is captured with diffused light, both will be captured in white on the image. It has the property of being difficult.

  The mounting stage 2 is configured to mount the printed wiring board 100 and to reciprocate in one direction as indicated by an arrow 71 with respect to the base 3. The moving direction of the mounting stage is a direction orthogonal to the pixel arrangement direction of the color camera 5 described later.

  The colored light source 4 is a linear light source composed of a light emitting diode that emits colored light. In the present embodiment, red (wavelength 630 nm) light is emitted, but the wavelength of the colored light is not particularly limited. Further, the light may not necessarily be monochromatic light, and may be colored light having a certain width of wavelength. The colored light emitted from the colored light source may include, for example, three types of diodes of RGB, and may be configured to emit light of any color by emitting light by appropriately combining them.

  The colored light source 4 is preferably arranged so that the irradiation direction of the colored light has an angle A that is about 0 to 20 degrees with respect to the normal direction of the printed wiring board 100. If it exceeds 20 degrees, it will be easily influenced by the diffuse illumination mentioned later, and the inspection accuracy of the printed wiring board 100 will fall. In the present embodiment, the colored light source 4 irradiates the colored light Lc so as to have an angle of approximately 7 degrees with respect to the normal direction of the printed wiring board 100. As will be described later, since the color camera 5 and the colored light source constitute a specular reflection optical system, the camera and the colored light source are in a positional relationship in which regular reflection is performed, and the orientation is determined by the angle of the color camera 5. Composed.

  The width of the colored light source 4 is preferably larger than the width of the printed wiring board 100, but the width of the printed wiring board 100 is at a position 50 where the colored light Lc reaches the width of the printed wiring board 100. What is necessary is just to be comprised so that it may become larger than a dimension.

  The color camera 5 is composed of a linear sensor, and is arranged so as to be substantially parallel to the coloring light source and orthogonal to the moving direction 71 of the mounting stage 2. Further, the color camera 5 and the colored light source 4 constitute a regular reflection optical system in which colored light specularly reflected on the surface of the printed wiring board 100 is directly incident on the color camera 5. Since both the color camera 5 and the colored light source 4 are linearly configured, it becomes easy to allow only the regular reflection component of the colored light Lc to be incident on the color camera 5, and a more accurate regular reflection optical system is configured. be able to.

  That is, the colored light Lc irradiated from the colored light source 4 reaches the surface of the printed wiring board 100 and is reflected and diffused. The color camera 5 receives only the regular reflection component of the reached colored light Lc.

  FIG. 2B is a schematic diagram showing a modification of the regular reflection optical system of the printed wiring board inspection apparatus according to the present embodiment. In this modification, a prism 8 having a half mirror is configured, and the colored light source 4 emits colored light parallel to the surface of the printed wiring board 100. The colored light that has reached the prism 8 is bent in a direction perpendicular to the printed wiring board 100 by the half mirror and reaches the printed wiring board 100. The colored light regularly reflected on the surface of the printed wiring board 100 passes through the prism 8 and is arranged so as to be orthogonal to the surface of the printed wiring board 100 and reaches the color camera 5.

  In the specular reflection optical system having the configuration shown in FIG. 2B, the colored light is attenuated by the half mirror, so the image obtained by the color camera 5 becomes dark, but the color camera 5 is provided in a direction orthogonal to the printed wiring board 100. Therefore, an image of the printed wiring board can be taken with higher accuracy.

The white light source 6 is a diffused light source that emits white light Lw, and is provided at two locations. The white light source 6 is provided to irradiate the surface of the printed wiring board 100 over a wide area so that the regular reflected light of the white light reflected by the surface of the printed wiring board 100 does not reach the color camera 5 directly. Is arranged. That is, the white light source 6 forms a diffuse reflection optical system in relation to the color camera 5.
The white light source 6 is preferably arranged so that the irradiation direction of the white light Lw has an angle B that is about 30 to 60 degrees with respect to the normal direction of the printed wiring board 100. In the present embodiment, the angle B is configured to be 45 degrees. Moreover, in order to irradiate the surface of the printed wiring board 100 over a wide area, it is preferable to have an angle larger than the incident angle of the colored light source 4.

  Further, the colored light source 4 and the white light source 6 are configured so that the colored light Lc is slightly weaker than the white light Lw. Increasing the brightness of the colored light Lc increases the absolute amount of the specular reflection component of the colored light Lc in the silk area, which will be described later. As a result, the image of the silk area is easily affected by the colored light Lc. affect. In addition, the ratio of the light quantity of the colored light Lc and the white light Lw can be appropriately adjusted according to the characteristics of the inspection target.

  Next, the operation of the printed wiring board inspection apparatus 1 according to the present embodiment will be described. As described above, in the printed wiring board 100 in which each pattern region is formed, each pattern region has a visually different color due to a difference in constituent materials. However, if it is composed of a mirror surface with silver luster, the silk area printed with white ink is visually different, but in the image captured with white diffused light, both are captured in white, and the image is distinguished. Hard to stick. The printed wiring board inspection apparatus 1 according to the present embodiment uses a characteristic that the color of the light source itself becomes strong and visible when the specularly reflected light is viewed, and distinguishes both using colored reflected light. It is.

  FIG. 3A is a schematic diagram illustrating a state of light reflection and diffusion when colored light is incident on a silk region. Since the surface of the silk region is a diffusion surface, the incident colored light is diffused in various directions, and as a result, the proportion of the regular reflection component is reduced. Further, the color light Lc has a lower brightness than the white light Lw, and the white light Lw of the white light source 6 constituting the diffuse reflection optical system in relation to the color camera 5 is irradiated on the surface of the silk region. 5, the white light Lw of the white light source 6 is dominant. Accordingly, the silk part is imaged white in the image imaged by the color camera 5.

  On the other hand, in the metal region, the specular component of colored light is dominant. FIG. 3B is a schematic diagram illustrating a state of light reflection and diffusion when colored light is incident on a metal region. Since the metal region is formed of a mirror surface, the proportion of the regular reflection component of the colored light Lc is increased. Although the white light Lw is also irradiated to the metal region, since the proportion of the specular reflection component of the colored light Lc is large, when the color camera 5 that receives the specularly reflected light of the colored light Lc is captured, The reflection component becomes dominant, and the color of the colored light Lc is easily visible. That is, the metal region is imaged in a state of being colored in the color of the colored light Lc.

  As described above, the difference in color on the image between the metallic area having silver luster such as a solder leveler and a silver plated portion and the silk area can be taken, and the area division processing by the recognition inspection unit 7 can be easily performed.

  In the recognition inspection unit 7 that performs recognition and inspection of each area of the printed wiring board using the image data captured by the color camera 5, as described above, the metal area that is captured by being colored in the color of the colored light Lc. Then, based on the color information of the pixels with the silk area imaged in white, both are recognized and the defect inspection of the printed wiring board 100 is performed using the obtained image.

  Next, a processing procedure for inspecting a printed wiring board for defects using the printed wiring board inspection apparatus according to the present embodiment will be described. FIG. 4 is a flowchart showing a processing procedure for inspecting a defect of a printed wiring board using the printed wiring board inspection apparatus according to the present embodiment. These operations are controlled by a control unit (not shown).

  First, the control unit turns on the white light source 6 of the inspection apparatus and turns off the colored light source 4 (# 10). In this state, the printed wiring board 100 to be inspected placed on the placement stage 2 is irradiated with the diffused light of the white light source 6, and the white light Lw is applied to the color camera 5 by the surface of the printed wiring board 100. Only the diffused light diffused by is incident.

  Next, the control unit moves the mounting stage 2 to the initial position (# 11), starts imaging of the color camera 5 (# 12), and moves the mounting stage 2 in the forward direction (# 13). ). As described above, since the color camera 5 is provided in a direction orthogonal to the moving direction of the mounting stage 2, the imaging position of the color camera changes with the movement of the mounting stage 2, and the printed wiring board 100. The surface image is obtained.

  When the mounting stage 2 is moved to the end position (# 14), since the imaging of the image obtained by imaging the surface of the printed wiring board 100 (hereinafter referred to as the first image) is completed, the first image is recognized and inspected. 7 (# 15).

  Next, the control unit turns on the colored light source 4 (# 16). That is, both the colored light source 4 and the white light source 6 are turned on. In this state, both the regular reflection component of the colored light Lc and the diffusion component of the white light Lw are incident on the color camera 5. The amount of white light Lw may be adjusted.

  In this state, when the mounting stage 2 moves in the reverse direction (# 17), a surface image of the printed wiring board 100 is obtained by the color camera 5. As described above, the image obtained at this time (hereinafter referred to as the second image) is an image with different coloring in the metal region and the silk region.

  When the mounting stage 2 moves to the initial position (# 18), since the imaging of the second image obtained by imaging the surface of the printed wiring board 100 is completed, the control unit stores the second image in the recognition inspection unit 7 (#). 19).

  Next, the recognition inspection unit 7 divides each area of the printed wiring board 100 using the first image and the second image (# 20). As described above, each region of the printed wiring board 100 can be divided using the first image according to the difference in material. However, since the silk area and the metal area cannot be divided in the first image, they are divided using the second image. Division into each region is completed, and registration of reference information necessary for inspection is completed. Using these pieces of reference information, the recognition inspection unit 7 performs defect inspection of each region (# 21).

  As described above, according to the printed wiring board inspection apparatus according to the present embodiment, it is possible to easily discriminate between a metal region and a silk region that are difficult to discriminate with a camera having a diffusion optical system. Can do.

  In addition, this invention is not limited to the said embodiment, It can implement in another various aspect.

It is a perspective view which shows schematic structure of the external appearance of the inspection apparatus of the printed wiring board concerning embodiment of this invention. It is a schematic diagram which shows schematic structure at the time of paying attention to the optical system of the inspection apparatus of the printed wiring board of FIG. It is a schematic diagram which shows the modification of the regular reflection optical system of the inspection apparatus of the printed wiring board concerning this embodiment. It is a schematic diagram which shows the state of reflection and diffusion of light when colored light is incident on the silk region. It is a schematic diagram which shows the state of reflection and diffusion of light when colored light is incident on a metal region. It is a flowchart which shows the process sequence which performs the defect inspection of a printed wiring board using the inspection apparatus 311 installation of the printed wiring board concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inspection apparatus of printed wiring board 2 Mounting stage 3 Base 4 Colored light source 5 Color camera 6 White light source 7 Recognition inspection part 8 Prism Lc Colored light Lw White light

Claims (6)

An inspection apparatus that images a printed wiring board having a silver glossy metal area and a silk area on which ink printing has been performed on the surface of the substrate body, and divides the inspection into a metal area, a silk area, and other areas ,
A color camera arranged so that the surface of the printed wiring board can be imaged;
A white light source the irradiated with white diffused light at an angle of 30 to 60 degrees against the printed wiring board surface, is arranged so as to form a diffuse reflecting optical system and the color camera,
The colored light is emitted to the surface of the printed wiring board so that the illuminance is lower than the white light emitted from the white light source, and the regular reflection light of the colored light on the surface of the printed wiring board is directed to the color camera. A colored light source arranged at such a position as to enter,
Receiving image data of the printed wiring board imaged by the color camera, and recognizing the portion colored in the color of the colored light by the colored light source in the image data as the metal region, and separating the region from the silk region And a recognition inspection unit for inspecting the printed wiring board. The color camera is a linear sensor;
The colored light source is composed of a linear light source arranged to be parallel to the pixel array of the linear sensor,
The printed wiring board according to claim 1, further comprising a drive unit that moves the printed wiring board in a direction orthogonal to a pixel arrangement direction of the linear sensor with respect to the coloring light source and the linear sensor. Inspection device. The colored light is characterized in that it is a red light, the printed wiring board inspection apparatus according to any one of claims 1 or 2. The incident angle of the colored light source is characterized by being composed smaller than the incident angle of the white light source, a printed wiring board inspection apparatus according to any one of claims 1 to 3. A color camera arranged so that the surface of the printed wiring board can be imaged, and colored light is emitted to the surface of the printed wiring board, and the regular reflection light of the colored light on the surface of the printed wiring board is incident on the color camera. a colored light source is disposed at a position such that said irradiated with white diffused light at an angle of 30 to 60 degrees against the printed wiring board surface, they are arranged to form a diffuse reflecting optical system and the color camera An inspection method for inspecting a printed wiring board having a metal area having silver luster, a silk area, and a distinguishable area visually distinguishable from the metal area and the silk area, using an inspection apparatus having a white light source There,
The first image obtained by capturing only the white light source and capturing the printed wiring board is captured,
The second image obtained by imaging the printed wiring board by turning on the white light source and the colored light source,
Based on the color information of each pixel displayed in the first image, it is possible to determine a region division between the distinguishable region and the other region including the metal region and the silk region ,
A method for inspecting a printed wiring board, comprising: determining a region division between the metal region and the silk region based on color information of each pixel displayed in the second image. 6. The printed wiring board inspection according to claim 5, wherein the brightness of white light emitted from the white light source is changed in the step of capturing the first image and the step of capturing the second image. Method.

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