JP4100376B2 - Surface condition inspection method and apparatus, and inspection image generation apparatus - Google Patents

Description

  The present invention relates to a technique for inspecting a surface state using a two-dimensional image of an inspection object obtained by a line sensor using an object having an inclined surface on the surface, such as solder on a component mounting board, as an inspection object. In particular, the present invention relates to a method and apparatus for generating a two-dimensional image in which a color distribution corresponding to an inclined state appears by illumination using a plurality of color lights, and executing the inspection.

  The applicant has previously developed an apparatus for automatically inspecting a soldering site on a substrate by an image processing technique using the specular reflectivity of the soldering site (see Patent Document 1).

Japanese Patent Publication No.6-1173

  The optical system of the inspection apparatus disclosed in Patent Document 1 is composed of three annular light sources having different diameters and a two-dimensional imaging device. Each light source emits red, green, and blue color lights, and the two-dimensional imaging device is arranged at a position corresponding to the center of these light sources with the optical axis directed in the vertical direction.

  In the above configuration, the color light irradiated on the surface of the solder from each light source is specularly reflected. Among these, since the specular reflected light of the color light from the angle direction corresponding to the direction of the imaging device is incident on the imaging device with respect to the inclined surface of the solder, the solder portion on the image is in a direction in which the gradient changes. Along each of the colors, red, green, and blue colors are distributed. Therefore, by registering each color pattern that appears in a well-shaped solder image and comparing each color pattern in the image to be inspected with the registered color pattern, the quality of the solder surface state is determined can do.

  Next, there are apparatuses disclosed in Patent Documents 2 and 3 as apparatuses for performing inspection using a line sensor. In the inspection apparatuses of these documents, an optical system in which a plurality of linear light sources are arranged along the imaging target region of the line sensor is used.

Japanese Patent No. 3341963 Japanese Patent No. 3170598

  In the apparatus described in Patent Document 2, an inspection based on the same principle as that of Patent Document 1 can be executed by irradiating a plurality of color lights from different angles to the imaging target region of the line sensor. Further, in the apparatus disclosed in Patent Document 3, a half mirror is interposed in the optical path of one light source, so that illumination from an oblique direction and illumination from directly above can be performed simultaneously on the inspection object. ing.

  When an inspection based on the same principle as in Patent Document 1 is performed with an optical system configured as in Patent Documents 2 and 3, the color distribution state on the image differs depending on the relationship between the solder inclined surface and the imaging target region. . For example, when the direction in which the solder gradient changes is orthogonal to the imaging target region, the light from each linear light source is emitted from the front side with respect to the solder slant surface. Color light can be irradiated under the same conditions as in the case, and an image in which each color is distributed along the direction of change in gradient can be obtained. On the other hand, when the direction in which the gradient changes is in the direction along the imaging target region, each color light is emitted from the side of the solder inclined surface, as described above. It is difficult to obtain an image with a color distribution.

  As described above, when a line sensor or a linear light source is used, the color distribution state differs depending on the mounting direction even for the same type of components. Therefore, when performing automatic inspection, it is necessary to register a color pattern for each mounting direction. In addition, when working to determine the inspection standard for this automatic inspection or when performing visual inspection, the image displayed on the monitor will be used, but the way it looks depends on the mounting direction of the parts Visibility is poor, there is a risk that the work may be hindered or misjudged.

  Furthermore, when each light source is located on the side of the inclined surface, depending on the inclined state of the solder, no specular reflected light of any color will enter the line sensor, and only an image close to black may be obtained. There is sex. In such a case, it is difficult to execute the inspection based on the color distribution.

The present invention has been made paying attention to the above-mentioned problems, and no matter what relationship the direction in which the gradient of the inspection target changes at the start of imaging changes with respect to the arrangement of the light source , An object of the present invention is to enable inspection with stable accuracy by generating an image in which a color distribution pattern representing a direction appears in a unified state .

In the surface condition inspection method according to the present invention, a plurality of linear light sources arranged along an imaging target area of a line sensor irradiate the imaging target area with a plurality of colored lights from different angular directions, in the generated two-dimensional color image of the inspection object by repeating the scanning of the line sensor while changing the relative position of the test object with respect to the imaging target region, said object using a two dimensional color image generated Inspecting the surface state of an object, in a plurality of states with different orientations of the inspection object with respect to the imaging target region, a process of generating a two-dimensional color image of the inspection object is executed, and a plurality of generated Using one of the two-dimensional color images as a reference, the other image is converted so that the orientation and position of the inspection object on the other images are aligned with the reference image. Thereafter, each image is synthesized by calculating an average value for each gradation of R, G, and B for each set of pixels having a correspondence relationship between the images, and an inspection is performed using the image obtained by this synthesis processing. It is characterized by performing .

  In the above, the plurality of linear light sources are light sources having a linear shape with a predetermined length or a gentle curvature close to a straight line, and may be configured as a fluorescent lamp or an aggregate of a plurality of light emitters (LEDs, etc.). it can. These light sources are preferably provided at different height positions for each emission color with the length direction along the imaging target region. Further, for any color light, two or more light sources can be arranged so as to be symmetric with respect to the imaging target region. Further, as in Patent Document 2 described above, a half mirror may be interposed in a part of the light paths of these light sources so that illumination from an oblique direction and directly above can be performed simultaneously on the imaging target region. .

  The line sensor generates image data for one line by a process of sequentially discharging the accumulated charge of each pixel. The process of generating image data for one line is called scanning. In the above method, a two-dimensional image including the entire image of the inspection target can be generated by repeating scanning while moving the inspection target relative to the imaging target region.

According to the above method, since a plurality of images reflecting different illumination states are acquired for one inspection object, and these images are averaged, the inspection object at the time of the first imaging is in any direction. The color distribution state in the final inspection image can be made uniform even when facing the direction.

  In addition, when performing the above-described averaging process, it is desirable to adjust the positional deviation and distortion between the images. In addition to the addition averaging process, the image composition process can include a correction process for the addition average image such as brightness correction.

  According to the above method, the same method is executed in advance on the object of the model, the reference color pattern is extracted and registered from the image after the synthesis process, and the color pattern extracted from the synthesized image at the time of inspection is registered. Inspection can be performed by collating with the registered color pattern. In this case, the same registered pattern can be used for the same kind of inspection object. In addition, when visual inspection is performed by displaying an inspection image, a unified color distribution state is displayed regardless of the orientation of the inspection object, so that there is no possibility of erroneous determination.

In the above method, when the solder on the component mounting board is used as an inspection object, in a preferred embodiment, the process of acquiring a two-dimensional color image of the inspection object is executed twice, and the inspection object for the imaging target region is also processed. The orientation is changed by 90 ° after the first treatment. This is because most components on the board are mounted with their main axes corresponding to the horizontal or vertical direction of the board. According to the above aspect, when the component is mounted in any direction, the image when the light is irradiated from the front side and the image when the light is irradiated from the side side on the inclined surface of the solder, and Can be obtained. Therefore, by combining these images, it is possible to obtain an image in which the distribution state of each color is unified.

Next, an inspection image generating apparatus according to the present invention includes: an imaging unit including a line sensor; and the imaging target region of the line sensor so that a plurality of color lights can be irradiated from different angular directions. a plurality of linear light sources deployed along, by repeating the scanning of the line sensor while changing the relative position of the test object with respect to the imaging target region under illumination by the respective linear light source, of the test object Image generating means for generating a two-dimensional color image for inspecting the surface state. Further, the image generation means sets a plurality of states in which the orientation of the inspection object with respect to the imaging target region is different by the conversion means for converting the orientation of the inspection target with respect to the imaging target region, and the conversion means. In each state, an image acquisition unit that executes a process of acquiring a two-dimensional color image of the inspection object, and one of a plurality of two-dimensional color images acquired by the image acquisition unit is used as a reference. After the other image is converted so that the direction and position of the inspection object are aligned with the reference image, the average value for each gradation of R, G, and B is calculated for each set of pixels having a correspondence relationship between the images. Image combining means for combining the images.

  In the above, the imaging unit can be configured as a line sensor camera including the line sensor, the lens, and the like. The plurality of linear light sources are the same as described above. Each of the image acquisition means and the image composition means can be configured by a computer in which a program corresponding to the means is set. Furthermore, the image acquisition means can include an inspection object or a moving mechanism for moving the imaging means and the light source.

  The conversion means of the image acquisition means can be constituted by an imaging means or a rotation mechanism that rotates the inspection object relative to each linear light source. Or it can also be set as the rotation mechanism which rotates an imaging means and a light source with respect to a test subject. Further, in the case where a plurality of optical systems using the imaging unit and each linear light source are provided and the inspection object is sequentially sent to each optical system, a conversion unit can be provided in the conveyance path between the optical systems.

  Furthermore, the inspection image generation apparatus according to a preferred aspect includes display means for displaying the composite image generated by the image composition means.

  According to the above-described inspection image generation apparatus, if the inclination state of the inspection object is good, it is possible to generate an inspection image in which the color distribution state is unified regardless of the orientation thereof, and is stable. An inspection can be performed.

The surface state inspection apparatus according to the present invention includes the same imaging means, a plurality of linear light sources, and image generation means as those of the inspection image generation apparatus. The surface condition inspection apparatus further includes a memory for storing reference image data generated by the image generation unit for the inspection object, and a two-dimensional color image generated by the image generation unit. Discriminating means for discriminating the quality of the surface state of the inspection object as compared with the reference image data.
According to this surface condition inspection apparatus, even if the direction of the inspection object is different, if the inspection object is of the same type, the reference image data can be made one. Therefore, the memory capacity can be saved and an efficient inspection can be performed.

According to the present invention, regardless of the state of the inspection object relative to the imaging target region at the start of imaging, the color distribution pattern representing the direction of the gradient change when the tilt state is good is unified. Therefore, an image with a stable state can be generated, and an accurate inspection can be performed using the image.

FIG. 1 shows a configuration example of a substrate inspection apparatus to which the present invention is applied.
This substrate inspection apparatus is for inspecting a component mounting substrate 5 (hereinafter simply referred to as “substrate 5”) that has undergone each process of solder application, component mounting, and solder heating treatment. The unit 2, the controller 3, the substrate stage 4, and the like.

  The line sensor camera 1 has a line sensor 10 and a lens which will be described later. The light projecting unit 2 is provided with two linear light sources that emit light of each color of red, green, and blue (in FIG. 1, 21 light sources of red (R), green (The light source of (G) is shown as 22 and the light source of blue (B) is shown as 23.) These light sources 21, 22, and 23 are fluorescent lamps or a plurality of LEDs arranged in a line, and are arranged with their length directions aligned with the imaging target area of the line sensor camera 1. The light sources having the same color are arranged so as to be symmetric with respect to the optical axis of the line sensor camera 1. Further, a red light source 21 is arranged at the highest position, a green light source 22 is arranged next, and a blue light source 23 is arranged next. The higher the position of the light source, the closer to the optical axis of the line sensor camera 1. . With such an arrangement, it is possible to irradiate each color light from different angular directions to the imaging target region.

The light projecting unit 2 can also be configured as shown in FIG. 2 includes linear light sources 21, 22, and 23 similar to those in FIG. 1, and a half mirror 25 is provided between the light source 21 and the line sensor camera 1, and the half mirror 25 Separately, a linear light source 24 in which LEDs are arranged is provided at a position corresponding to the optical axis. According to this configuration, it is possible to simultaneously irradiate the imaging target region with light from an oblique direction and light from directly above. Moreover, it becomes easy to observe a flat surface by the light from right above. The light from directly above is desirably white light or red light.

  The substrate stage 4 includes a moving mechanism (not shown) for moving the stage in a direction orthogonal to the imaging target region (left and right in the drawing), and a rotating mechanism (not shown) for rotating the stage by a predetermined angle. Z.) is provided.

  In addition to the CPU 31 and the memory 32, the controller 3 includes an imaging control unit 33, an illumination control unit 34, a substrate stage control unit 35, an input / output unit 36, and the like. The imaging control unit 33 includes a circuit for generating a drive signal for the line sensor camera 1, an output circuit for the signal, an input circuit for capturing image data from the line sensor camera 1, and captured image data An A / D conversion circuit for digitally converting the signal is included. The illumination control unit 34 is for controlling the lighting / extinguishing operation of each light source and adjusting the light quantity at the time of lighting. The substrate stage control unit 35 is for controlling the operation of the moving mechanism and rotating mechanism of the substrate stage 4 described above. The input / output unit 36 is configured by an interface circuit for taking in setting data relating to inspection from a keyboard, a mouse, or the like, or outputting an image for inspection to a monitor.

  In the memory 32, a program storage unit 32a and an inspection data storage unit 32b are set. The program storage unit 32a stores various programs for inspection, fixed data, and the like. In the inspection data storage unit 32b, inspection area setting data, a binarization threshold for extracting each color in the inspection area, a reference color pattern to be extracted by the binarization threshold, and a reference color Various data relating to the inspection, such as a determination criterion for comparing the pattern with the color pattern to be inspected, is stored (hereinafter, these data are collectively referred to as “inspection data”). In addition, an area for temporarily storing an image of the board to be inspected is set in the memory 32.

  In the above, the CPU 31 generates a two-dimensional image for inspection of the substrate 5 by controlling the operations of the line sensor camera 1 and the substrate stage 4 using the imaging control unit 33 and the substrate stage control unit 34. Perform inspection.

  FIG. 3 shows a specific example of an imaging process for generating an inspection image in the substrate inspection apparatus. 3 schematically shows the relationship between the optical system of FIG. 1 and the substrate 5 as seen from above, and the lengths of the line sensor 10 and the light projecting unit 2 in the camera 1 are the same. The pixel arrangement of the line sensor 10 is shown as being arranged in the same direction as the length direction of the light projecting unit 1.

  In this embodiment, a two-dimensional image including the entire image of the substrate 5 is generated by repeating the scanning of the line sensor 10 while moving the substrate 1 along the direction orthogonal to the imaging target region of the line sensor 10. To do. Hereinafter, this process for generating a single two-dimensional image is referred to as “imaging process”. In this embodiment, after performing one imaging process on the substrate 5 set on the substrate stage 3, the substrate 5 is returned to the initial position and rotated by 90 °, and the imaging process is performed again. Yes.

  Furthermore, in this embodiment, by cutting out images of the same component from the two two-dimensional images obtained by the two imaging processes, and synthesizing these images with the orientation of the components aligned, An image for inspection is generated. Hereinafter, the meaning of the imaging process shown in FIG. 3 and a specific method for creating an image for inspection will be described.

  4 (1) shows a spherical solder (6 in the figure) on the substrate 5, and FIG. 4 (2) shows an image obtained by imaging the solder 6 with the optical system of FIG. Indicates. A dotted arrow C in FIG. 4B corresponds to the direction in which the solder 6 is moved with respect to the imaging target area of the line sensor 10. In FIGS. 4 (2) and 6, the red, green, and blue color regions are indicated by R, G, and B, respectively. Further, the filled area in the figure is a shadow area generated because no color light is incident on the line sensor.

In the spherical solder 6 as shown in FIG. 4A, it can be considered that the same gradient change occurs in all directions. Among these, a color distribution reflecting a change in gradient appears in a range in which light from each of the light sources 21, 22, and 23 can be received from the front side. In the image of FIG. 4 (2), a color distribution reflecting the change in the gradient occurs in the range in which the gradient changes along the direction of the arrow C. On the other hand, the change direction of the gradient is almost the same as the length direction of the light source. In the same central part, the specular reflected light of any color cannot be guided to the line sensor 10, and a shadow is generated.
Even in the range where the concentration gradient changes along the direction of the arrow C, shadows are generated on the central portion of the solder near the flat surface and the steep slope near the substrate surface.

  In the image of the spherical solder 6 described above, since the same gradient change occurs in all directions, no matter which direction the line sensor 10 is scanned with respect to the solder 6, along the direction crossing the scanning direction, FIG. It can be considered that a color distribution similar to (2) occurs. On the other hand, in the solder fillet, since the range in which the inclined surface is formed is limited, if the light from each of the light sources 21, 22, and 23 is not irradiated from the front side to the inclined surface, the color reflecting the inclined state It becomes difficult to obtain an image having a distribution.

  FIG. 5 shows a chip component 7 that is a typical inspection target, along with a direction in which the chip component 7 is moved with respect to the line sensor 10. In the figure, reference numeral 71 denotes a component body, and 72 denotes an electrode on the component side. Reference numeral 8 denotes a solder fillet for joining the electrode 72 and the substrate side electrode (land).

Arrow M _A along the width direction of the component 7, corresponds to the direction of varying the slope of the solder fillet 8. The other arrow M _B is a direction orthogonal to the arrow M _A. According to the method of FIG. 3, after performing the first imaging processing while moving along the part 7 in the direction of arrow M _A, the part 7 rotate 90 °, moving along the direction of arrow M _B However, the second imaging process is performed.

FIG. 6 shows a specific example of an image obtained by the above two imaging processes by extracting one fillet 8 portion of the chip part 7 of FIG. (A) in the figure, that the cross-sectional shape of the fillet 8 along the direction of arrow M _A of FIG. 5, associates the image obtained this fillet 8 when moving along the arrow M _A It is. On the other hand, (B) is a cross-sectional shape of the fillet 8 along the direction of arrow M _B of FIG. 5, in which the fillet 8 associates the image obtained when moving along the arrow M _B is there. In any case, the fillet 8 moves in a direction orthogonal to the imaging target region of the line sensor 10 and the length direction of the light sources 21, 22, and 23.

When moving the fillet 8 in the direction of arrow M _A, compared inclined surface of the fillet 8, color light can be emitted from the front side. That is, when the line sensor 10 is scanning a predetermined line on the inclined surface, light from any one of the light source groups (including one of the light sources 21, 22, and 23) on both sides of the line sensor 10 The colored light according to the inclination of the inclined surface is incident on the line sensor 10. As a result, a color distribution corresponding to the change in gradient appears in the fillet on the image. However, even in this case, there is a possibility that a shadow is generated in a portion close to a steep slope and a flat surface.
On the other hand, in the case of moving the fillet 8 in the direction of arrow M _B, each color light is to be irradiated from the side end of the inclined surface. In this case, if there is almost no change in gradient along the direction of arrow B, no specular reflected light of any color will enter the line sensor 10 and a shadow will be generated in the fillet on the image.

  In this embodiment, images A and B of the fillet 8 are cut out from images obtained by two imaging processes, respectively. At this time, by rotating the image B cut out from the second image by 90 °, the orientation of the fillet between the images A and B is aligned, and these images A and B are synthesized by the addition averaging process.

  In the averaging process, an average value of each gradation of R, G, and B is obtained for each corresponding pixel of images A and B. Here, since each pixel of the image B is close to black, it can be considered that all the gradations of R, G, and B have values close to 0. Therefore, the color distribution state in the image A is reflected in the image after the averaging process.

  Most components on the board are mounted with the main axis oriented horizontally or vertically. Therefore, according to the method of FIG. 3, it is possible to obtain an image when the inclined surface is illuminated from the front side and an image when the inclined surface is illuminated from the side side for most soldered portions on the substrate. it can. Therefore, if the tilt state of the solder is normal, regardless of whether or not the direction of the change in the slope of the inclined surface immediately after being placed on the substrate stage 4 occurs in the direction crossing the imaging target area of the line sensor 10, A unified distribution pattern can be obtained for colors in the addition average image.

  Note that the image of the fillet 8 shown in FIG. 6 is schematic, and depending on the shape of the fillet 8, the change in the gradient seen from this direction is also reflected in the image B when illuminated from the side. Colors may appear. However, if this reflects the good shape of the fillet 8, the color distribution state of the addition average image is only slightly different from that in FIG. 6, and is used as an image for inspection. There is no problem.

  In an actual inspection, an image of the entire part including the fillet is cut out and subjected to two imaging processes and addition averaging processes. Therefore, the images of the parts and electrodes are also added and averaged. The addition average images corresponding to the parts and electrodes need not be regarded as a problem for the same reason as described above for the fillet.

  In the board inspection apparatus of this embodiment, the above-described two imaging processes are executed in advance using the model of the board 5 to be inspected, and the image shown in FIG. An addition averaging process is performed to generate an image for teaching. This teaching image is displayed on a monitor, and registration work such as the binarization threshold value and the determination criterion is performed by an attendant. The inspection area setting data for each component can be created using CAD data or the like. The reference color pattern is automatically extracted by registering a binarization threshold value.

  FIG. 7 shows an inspection procedure after the teaching work is completed. In FIG. 7 and the following description, each step (STEP) is abbreviated as “ST”.

  This inspection starts when an attendant inputs the name of a substrate to be inspected. First, in ST1, inspection data corresponding to a substrate to be inspected is read from the inspection data storage unit 32b and set in the work area of the memory 32.

  In ST2, the substrate 5 to be inspected is carried into the substrate stage 4. In the next ST3, the first imaging process is performed on the substrate 5 in the manner described above. Next, in ST4, the substrate stage 4 is rotated by 90 °, and in ST5, the second imaging process is executed.

When the second imaging process is completed, ST6 to ST12 are executed for each component to be inspected using the two acquired images.
In ST6, inspection areas a and b are set on the two images for one specific part, respectively. FIG. 8 shows an example of setting the inspection area. In this example, A1 is an image obtained by the first imaging process, and 5A is a substrate in the image. On the other hand, B1 is an image obtained by the second imaging process, and 5B is a substrate in the image. The sizes of the inspection areas a and b and the relative positional relationship with respect to the parts are adjusted to be the same.

  Returning to FIG. 7, in the next ST7, an image in each of the inspection areas a and b is cut out (hereinafter, an image cut out from the area a is referred to as an image A, and an image cut out from the area b is referred to as an image B). In ST8, the image B is rotated by 90 ° in the direction opposite to the rotation of the substrate at the time of imaging. In ST9, the positional deviation amount (x, y, θ) with respect to the other image A is extracted from the rotated image B.

Of the positional shift amounts extracted in ST9, x indicates a shift in the horizontal direction (x-axis direction) of the image, y indicates a shift in the vertical direction (y-axis direction) of the image, and θ indicates a rotational shift. Equivalent to. In order to obtain these shift amounts, for example, the images A and B are converted into monochrome images, and edge pixels and their edge codes are extracted. Then, a pair of edge pixels whose edge code difference is within a predetermined value is extracted as a corresponding pixel, and an average value of x-coordinate differences between corresponding edge pixels is calculated as an average of the difference between the shift amounts x and y coordinates. The value is the shift amount y, and the average value of the edge code differences is the shift amount θ.
The edge code is angle data indicating the direction in which the density gradient changes with the edge pixel as a reference. For details, see Patent Document 4 below.

JP 2002-203233 JP

  When the positional deviation amount is obtained in this way, in ST10, the positional deviation between the images A and B is corrected by affine transformation of the image B based on the positional deviation amount. In ST11, the image synthesis process is executed by executing an addition averaging process for each corresponding pixel between the corrected image B and the image A.

  After this, patterns of each color are extracted from the composite image obtained by the process of ST11, and the suitability of the soldering part is checked by comparing these color patterns with the reference color pattern registered as the inspection data. Determine. In addition, in ST11, inspections such as presence / absence of components and displacement can be performed.

  Similarly, the inspection is advanced by executing ST6 to 12 for each part. The inspection result can be stored in a work area of the memory 32 or the like.

  When the inspection for all components on the substrate 5 is completed, ST13 becomes “YES” and the process proceeds to ST14. In ST14, the inspection for each component is integrated to determine whether the entire board is good or not, and the determination result is output. Further, when a defect determination is output, an inspection result concerning a component determined to be defective is also output.

  In this way, the inspection for one substrate 5 is completed. Further, when inspecting the same type of substrate 5, the process returns from ST15 to ST2, and the same procedure is repeated. When the inspection for all the substrates 5 to be inspected is completed, ST15 becomes “YES” and the processing is ended.

  According to the above procedure, even if the main axis of each component is oriented in any direction with respect to the imaging target region of the line sensor 10 and the length direction of the light sources 21, 22, and 23, the soldering portion of the component is determined. Inspection can be performed based on uniform standards. Further, even if a component is mounted in such a direction that a color distribution reflecting the solder inclination state cannot be obtained, an image with a clear color distribution can be obtained by averaging the two images. Therefore, the reference color pattern stored in the inspection data storage unit 32n can be unified for each component type, and the inspection can be executed with stable accuracy.

  Also, at the time of teaching prior to the inspection, the same two imaging processes are performed on the model substrate, the addition average image of each image is displayed, and the registration work is performed. Therefore, the color distribution in the displayed image is determined. , Can be unified for each type of parts. Therefore, there is no possibility that the worker will be confused, and the registration work can be performed efficiently.

  In the above embodiment, the substrate is rotated by 90 ° during the second imaging process, but instead, the optical system may be rotated by 90 ° as shown in FIG.

  Further, as shown in FIG. 10, the image pickup processing by the two sets of optical systems 100 </ b> A and 100 </ b> B may be sequentially executed while the substrate 5 is conveyed by the belt conveyor 9. The two optical systems 100A and 100B in this example both have the line sensor 10 and the light projecting unit 2 similar to those in FIG. 3, and are arranged in a state where the length direction corresponds to the width direction of the conveyor 9. The In this example, by switching the transport direction of the belt conveyor 9, the horizontal width direction of the substrate 5 is moved with respect to each optical system 100A, and the vertical width direction of the substrate is moved with respect to the optical system 100B. Therefore, an image similar to the example of FIG. 3 or FIG. 9 can be obtained. However, in the case of this example, parameters necessary for correcting differences between the optical systems 100A and 100B, such as magnification, aberration (distortion), misregistration amount, hue, and brightness level, are obtained in advance, and imaging processing is performed. It is necessary to perform the averaging process after correcting each subsequent image with the parameters.

It is a figure which shows the structure of the board | substrate inspection apparatus concerning one Example of this invention. It is a figure which shows the other example of an optical system. It is a figure which shows the specific example of an imaging process. It is a figure which shows the structure of a spherical solder and the image obtained by imaging this solder with the optical system of FIG. It is a figure which shows the structure of a chip component with the moving direction of the component in the case of imaging. It is a figure which shows the specific example of the image obtained by two imaging processes, and the image after an addition average process about a solder fillet. It is a flowchart which shows the procedure of a board | substrate inspection. It is a figure which shows the example of a setting of a test | inspection area | region. It is a figure which shows the other example of an imaging process. It is a figure which shows the example in the case of performing an imaging process with two sets of optical systems.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Line sensor camera 2 Light projection part 3 Controller 4 Board | substrate stage 5 Board | substrate 8 Fillet 10 Line sensors 21, 22, and 23 Linear light source 31 CPU
32 Memory 33 Imaging control unit 35 Substrate stage control unit 36 Input / output unit

Claims (5)

A plurality of linear light sources arranged along the imaging target area of the line sensor irradiate the imaging target area with a plurality of color lights from different angular directions, and the inspection target with respect to the imaging target area is illuminated under the illumination state . In a method of generating a two-dimensional color image of the inspection object by repeating scanning of a line sensor while changing a relative position, and inspecting a surface state of the inspection object using the generated two-dimensional color image ,
In a plurality of different states of the inspection object with respect to the imaging target region, a process of generating a two-dimensional color image of the inspection object is executed, and one of the generated two-dimensional color images is used as a reference After the other image is converted so that the orientation and position of the inspection object on the other image are aligned with the reference image, each gradation of R, G, B for each set of pixels having a correspondence relationship between the images A surface condition inspection method comprising: combining each image by calculating an average value for each, and performing an inspection using an image obtained by the combining process . In the surface state inspection method according to claim 1 ,
The inspection object is solder on a component mounting board, and a process of acquiring a two-dimensional color image of the inspection object is executed twice, and the direction of the inspection object with respect to the imaging target area is set to the first time A surface condition inspection method in which the surface is changed by 90 ° after the treatment. Imaging means including a line sensor;
A plurality of linear light sources arranged along the imaging target area so that the imaging target area of the line sensor can be irradiated with a plurality of colored lights from different angular directions;
A two-dimensional color image for inspecting the surface state of the inspection object is obtained by repeating scanning of the line sensor while changing the relative position of the inspection object with respect to the imaging target region under illumination by each linear light source. Image generating means for generating,
The image generating means sets a plurality of states in which the orientation of the inspection object with respect to the imaging target area is different by the conversion means for changing the orientation of the inspection target with respect to the imaging target area, and the conversion means. in the state, an image acquisition unit that executes a process of acquiring two-dimensional color image of each inspection object, based on the one of the plurality of 2-dimensional color image by the image acquisition unit has acquired, inspected on other images After the other image is converted so that the orientation and position of the object are aligned with the reference image, an average value for each gradation of R, G, and B is calculated for each set of pixels having a correspondence relationship between the images. And an image synthesizing unit that synthesizes the images. The apparatus of claim 3 , wherein
An inspection image generating apparatus, further comprising display means for displaying the combined image generated by the image combining means. Imaging means including a line sensor;
A plurality of linear light sources arranged along the imaging target area so that the imaging target area of the line sensor can be irradiated with a plurality of colored lights from different angular directions;
A two-dimensional color image for inspecting the surface state of the inspection object is obtained by repeating scanning of the line sensor while changing the relative position of the inspection object with respect to the imaging target region under illumination by each linear light source. Image generating means for generating;
For the inspection object, a memory for storing reference image data generated by the image generation means;
A determination unit that compares the two-dimensional color image generated by the image generation unit with reference image data in the memory to determine whether the surface state of the inspection object is good;
Output means for outputting a pass / fail judgment result by the discrimination means,
The image generating means sets a plurality of states in which the orientation of the inspection object with respect to the imaging target area is different by the conversion means for changing the orientation of the inspection target with respect to the imaging target area, and the conversion means. In the state, the image acquisition means for executing the process of acquiring the two-dimensional image of the inspection object, and the inspection object on other images based on one of the plurality of two-dimensional color images acquired by the image acquisition means By converting the other images so that their orientations and positions are aligned with the reference image, and then calculating an average value for each gradation of R, G, and B for each set of pixels having a correspondence relationship between the images. An inspection image generating apparatus including image combining means for combining each image .

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