JP2015210226A - Visual inspection device and visual inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual inspection device and a visual inspection method, in which, in the visual inspection such as, for example, a solder fillet, occurrence of excessive detection (misinformation) is suppressed and inspection can be performed at a high speed while holding the high percentage of defect-free product.SOLUTION: A visual inspection device includes: an illumination device 5 which is provided so as to irradiate a substrate 1 as an inspection workpiece with inspection light, from a plurality of positions, having light colors different from each other at the positions.; a color imaging device 6 which is arranged and installed so as to receive reflection light irradiated from an illumination device and reflected by the inspection workpiece; and an information processing device 60 which, based on output of the color imaging device, determines a state of the inspection workpiece from individual information on light colors obtained by individual imaging region of the inspection workpiece.

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method that can be preferably used for, for example, an appearance inspection of a soldered state after mounting an electronic component on a board.

  As a conventional appearance inspection device for inspecting the soldering appearance, etc., in order to obtain the shape of the fillet of the soldering part, it is equipped with multiple ring-shaped illuminations with different heights or diameters, and the reflected light of each illumination Is picked up by a camera, and angle information of the solder fillet is acquired to perform an appearance inspection (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 8-152311 (first page, FIGS. 1 to 3)

  In the appearance inspection apparatus as described above, the angle component of the solder fillet can be obtained by the reflected light from the angle of the ring-shaped illumination. For example, a fillet such as a component float (defective) and an excessive amount of solder (good product). There is a case where there is a discontinuous shape in the vertical direction that cannot be determined only by angle information. In order to suppress oversight, these must be judged as defective, so even if it is a non-defective product, so-called over-detection (false alarm) is detected and it is the ratio of those that passed the inspection in one shot. There is a problem of lowering the direct rate. For this reason, in the prior art, excessive solder (defective) is detected by dividing the ring illumination in the circumferential direction and switching and irradiating only the illumination facing the soldering portion. However, with this method, it is not possible to discriminate over-soldering (non-defective products), and it is necessary to switch the illumination, resulting in a problem that the inspection time becomes long.

  The present invention has been made to solve the above-described problems. For example, in appearance inspection of a solder fillet or the like, occurrence of overdetection (false information) is suppressed, and high speed is maintained while maintaining a high straightness rate. An object is to obtain an appearance inspection apparatus and an appearance inspection method capable of performing inspection.

The visual inspection apparatus according to the present invention includes an illumination device provided to irradiate inspection light of different light colors depending on the position from a plurality of positions on an inspection work, and the inspection that is irradiated from the illumination device. A color imaging device arranged to receive reflected light reflected by the workpiece, and information on the inspection workpiece based on information for each light color obtained for each imaging area of the inspection workpiece based on the output of the color imaging device And an information processing device for determining the state.
In addition, the visual inspection method according to the present invention irradiates the inspection work with inspection light having different light colors depending on the position from a plurality of positions, and reflects the reflected light reflected by the inspection work with a color imaging device. It receives light and determines the state of the inspection work from information for each light color obtained for each imaging region of the inspection work based on the output of the color imaging device.

According to the appearance inspection apparatus of the present invention, a color imaging apparatus that irradiates inspection light of different light colors depending on the position from a plurality of positions, and receives reflected light reflected by the inspection work. Since the state of the inspection work is determined from the information for each light color obtained for each imaging area of the inspection work based on the output of the inspection work, it is possible to inspect various states of the inspection work without switching the illumination. It is possible to suppress the occurrence of over-detection (false alarm) and to perform inspection at high speed while maintaining a high direct rate.
Further, according to the appearance inspection method of the present invention, a color for irradiating the inspection work with inspection light of different light colors depending on the position from a plurality of positions and receiving the reflected light reflected by the inspection work. Since the state of the inspection work is determined from the information for each light color obtained for each imaging area of the inspection work based on the output of the imaging device, various states of the inspection work are inspected without switching the illumination. Therefore, the occurrence of overdetection (false alarm) is suppressed, and the inspection can be performed at high speed while maintaining a high straightness rate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows notionally the principal part of the external appearance inspection apparatus by Embodiment 1 of this invention. It is a figure which shows the structure of the illuminating device shown by FIG. It is a figure which illustrates the test | inspection model at the time of carrying out an external appearance test | inspection of the soldering state of the electronic component mounted in the board | substrate by the external appearance inspection apparatus shown by FIG. It is a flowchart explaining the operation example of the external appearance inspection apparatus by Embodiment 1 of this invention, and the external appearance inspection method.

Embodiment 1 FIG.
Hereinafter, a case where the appearance inspection apparatus according to Embodiment 1 of the present invention is used for appearance inspection of a soldered state of an electronic component mounted on a circuit board will be described with reference to the drawings. 1 is an overall configuration diagram conceptually showing the main part of an appearance inspection apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing the configuration of the illumination device shown in FIG. In the figure, a substrate 1 which is an inspection work has a terminal 2a of a soldered electronic component 2 and a solder fillet 3 which is a soldering portion for connecting the terminal 2a and an electrode (not shown) on the substrate. . The appearance inspection apparatus includes a transport stage 4 that holds the substrate 1, a ring-shaped illumination device 5 disposed above the transport stage 4 in the drawing, a color imaging device 6 that images a soldering state, and a transport stage 4. For each light color obtained for each imaging region of the inspection work based on the output of the stage control device 40 that moves the illuminating device to an arbitrary position in the XY-axis direction, the illumination control device 50 that controls the illumination device 5, and the color imaging device 6 And an information processing device 60 for determining the state of the solder fillet 3 from the above information.

  As shown in FIG. 2, the lighting device 5 is ring-shaped and the lighting area is equally divided into four in the circumferential direction as indicated by a, b, c and d, and the emission colors R (red) and G of the opposing areas are divided. (Green) and B (blue) are different from each other (for example, from the inner periphery side to the outer periphery side, the lighting area a is RGB while the opposing lighting area b is BGR), and the outside Three ring-shaped light source parts 51, 52, and 53 whose diameters are sequentially increased are arranged concentrically in multiple stages (three stages) in the Z-axis direction. The three ring-shaped light source units 51, 52, 53 are connected to the illumination control device 50, and the lighting areas (a to d) of the ring-shaped light source units 51, 52, 53 are individually turned on / off, illumination power, etc. It can be controlled arbitrarily. The illumination control device 50 is supplied with a stage position signal from the stage control device 40 and has a function of outputting an imaging / light emission signal (trigger signal) to the color imaging device 6 and the illumination device 5 in accordance with the inspection position. doing. The color imaging device 6 is connected to the information processing device 60 and is configured to determine whether the soldered state is good or not from the captured image data group. The accompanying devices such as a console and a display for displaying the determination result are not shown.

  In the first embodiment configured as described above, the illumination device 5 irradiates inspection light onto the solder fillet 3 portion of the substrate 1 which is an inspection work. The illumination device 5 is configured such that the lighting area, the emission color, and the positions of the ring-shaped light source units 51, 52, and 53 in the Z-axis direction are configured as described above. Since the color inspection light is irradiated, the solder fillet 3 is illuminated at a different angle. The inspection light applied to the solder fillet 3 generates reflected light in various directions depending on the shape such as the inclination angle of the surface of the solder fillet 3 and the position and light color of the light source of the inspection light. The reflected light is picked up by the color image pickup device 6 installed at a predetermined position in the upper part of the drawing, and the quality of the soldered portion is determined by the following procedure.

  Hereinafter, the terminal 2a of the electronic component 2 mounted on the substrate 1 in the left-right direction (X-axis direction) in the figure on the image captured by the color imaging device 6 exists, and the soldering portion on the right side of the electronic component 2 An operation example when the illumination device 5 of FIG. 2 is applied to the solder fillet 3 will be described with reference to FIGS. 3 and 4. 3 is a diagram illustrating an inspection model when visual inspection is performed on the soldering state of the electronic component 2 mounted on the substrate by the visual inspection apparatus shown in FIG. 1, and FIG. 4 is a first embodiment of the present invention. 5 is a flowchart for explaining an operation example and an appearance inspection method of the appearance inspection apparatus according to FIG. In FIG. 3, (a) soldered state good product, (b) solder low (defective), (c) excessive solder (defective), (d) excessive solder (good), (e) component floating. / It is a schematic diagram when unsoldering (defective) is seen from the side. Further, in the tables shown in FIGS. 3A to 3E, A to D are inspection areas obtained by dividing the inspection area in the column direction, and one row represents representative luminance described later measured in each inspection area. Shows the light color.

(Step S1)
An average value of luminance of each color in each column is obtained in the vertical direction (Y direction on the image, front and rear direction on the paper surface in FIGS. 1 and 3) with respect to the pixel groups in the inspection areas (A to D) set in advance. The highest average luminance measured in each column is set as the representative luminance. In the color scheme of the illuminating device 5 of FIG. 2, for example, in the soldered portion of FIG. 3A, the flat portion shown in the inspection areas (A) and (D) or a region close to flat is incident on the color imaging device 6. As is clear from the positional and angular relationship in the figure, the light was irradiated from the innermost R (red) of the lighting areas a and d and the innermost B (blue) of the lighting areas b and c. Since all of the reflected light components of the inspection light increase and the luminance of each of the R, G, and B colors measured by the color imaging device 6 is about the same, the representative luminance is R (red). Or it becomes the average brightness of B (blue). In the first row of FIG. 3, this is indicated as “R≈B” for convenience.

On the other hand, in the inspection areas (c) and (a) in FIG. 3 (a), the inclination angle of the surface of the solder fillet 3 increases, and as the angle gradually increases from the inspection area (c) to (a), The reflected light components incident on the color imaging device 6 increase in G and B based on the inspection light from the lighting area a in FIG. Therefore, the representative luminance is G (green) in the inspection area (c) in the soldering portion of FIG. 3A, and the representative luminance is B (blue) in the inspection area (b).
3A, the red component (R) inspection light emitted from the ring-shaped light source 53 in the lighting area b in FIG. 2 has an irradiation angle with respect to the solder fillet 3 as shown in FIG. Since it is low and is blocked by the top of the electronic component 2 and does not reach the solder fillet 3, the inspection light derived from the red component (R) in the lighting area b is not imaged in the inspection areas (c) and (b).

The inspection area (a) is actually set as a plurality of inspection areas as shown in FIG. 3 (c), assuming the existence of “excessive solder (defect)” as shown in FIG. 3 (c). Has been. 3 (a), (b), (d), and (e) are set as a plurality of inspection areas in the same manner as in FIG. 3 (c), but in order to avoid duplication of explanation. Here, one inspection area is used for convenience.
In addition, “BG” shown in one row in the inspection area (A) in FIG. 3B is “B” or “G” as the representative luminance, and is in the inspection area (A) in the inspection area (A). The near side is “B”, and the side near the inspection area (C) is “G”.
Further, “B> R” shown in one row in the right column of the inspection area (a) in FIG. 3C is “B” as the representative luminance, but the “R” component is not zero. Is shown.

(Step S2)
In step S1, a difference value dR between the representative luminance obtained for each inspection area (A to D) as described above and the average value of the luminance of the red (R) component in each column is obtained. The color component which gave the difference value dR to two lines of Fig.3 (a)-(e) is shown. For example, the case where the shape of the solder fillet 3 is shown in FIG.
In the inspection area (a) in FIG. 3A, the representative luminance is the average value of the luminance of the R (red) component (≈the average value of the luminance of the B (blue) component) as indicated by R≈B in one row. As such, the difference dR between the average luminance of the representative luminance of the inspection area (A) and the luminance of the red (R) component of the inspection area (A) is
dR = {average value of luminance of R (red) component} − {average value of luminance of R (red) component} = 0
It becomes.

In the inspection area (A) in FIG. 3A, the representative luminance is the average value of the luminance of the B (blue) component, and the average value of the luminance of the R (red) component is, as indicated by “B” in one row. Since it is substantially 0, the difference value dR between the average luminance of the representative luminance of the inspection area (A) and the luminance of the red (R) component of the inspection area (A) is
Since the luminance is the B (blue) component, the color component “B” is displayed with the difference value.
In the inspection area (c) of FIG. 3A, as indicated by “G” in one row, the representative luminance is the average value of the luminance of the G (green) component, and the average value of the luminance of the R (red) component is Since it is substantially 0, the difference dR between the average luminance of the representative luminance of the inspection area (c) and the luminance of the red (R) component of the inspection area (c) is
Since the luminance of the G (green) component is obtained, the color component “G” to which the difference value is given is displayed.
Since the inspection area (D) in FIG. 3A is the same as the inspection area (A), the average value of the representative luminance of the inspection area (D) and the luminance of the red (R) component of the inspection area (D) is calculated. The difference dR is
dR = {average value of luminance of R (red) component} − {average value of luminance of R (red) component} = 0
It becomes.

(Step S3)
If the difference value dR between the representative luminance of the inspection areas (A) and (C) and the average value of the red component is equal to or higher than a predetermined value α that is a preset threshold value for both inspection areas, the luminance is higher than that of red. It is determined that there is a high G (green) or B (blue) component, that is, the solder fillet 3 is present normally, and the inspection work is determined as “good”. Here, FIG. 3A corresponds to the above condition and is determined to be a non-defective product. The predetermined value α is statistically set by actually measuring each of a plurality of samples having a normal solder fillet and a plurality of samples having a defective solder fillet.
(Step S4)
When the difference value dR between the representative luminance of the inspection area (A) and the average value of the red component is equal to or higher than a predetermined value β (<α), there is a component of G (green) or B (blue). That is, although it is estimated that there are a small number of solder fillets, it is not appropriate to make a non-defective product, and it is determined that “solder is low (defective)”. Here, FIG. 3B corresponds to the above condition.

(Step S5)
If the difference value dR between the representative luminance of the inspection area (c) and the average value of the red component is equal to or higher than a predetermined value γ, it is determined that there is a non-flat portion, that is, a solder fillet. Bad) ”. Here, FIG. 3C corresponds to the above condition.
(Step S6)
The difference value dB between the representative luminance and the average value of the blue (B) components in each column is taken. The difference values are shown in the third row of FIG.

(Step S7)
If the difference between the representative luminance of the inspection area (A) and the average value of the blue component is a certain value δ or more, the blue component (B) of the lighting area b in FIG. Judgment is made and “part floating (defect)” or “unsoldered (defect)”. Here, FIG. 3E corresponds to the above condition.
(Step S8)
Other than the above is “excessive solder (good product)”. Here, FIG. 3D corresponds to the above condition.

  The above steps S1 to S8 are performed on the entire visual field of the inspection work. In this way, the illuminations facing each other with the inspection area at the center are made different colors, and by paying attention to the difference in the color components received by the color imaging device 6, the difference in the soldering state of the substrate 1 is emphasized, Things that have been difficult to distinguish, such as over-soldering (non-defective product) and part floating or non-soldering, can be discriminated without switching lighting, and the false alarm rate is suppressed. In addition, in the conventional method, since it is not possible to distinguish between the excessive solder (good product) of (d) in FIG. 3 and the component floating (unsoldered) of (e), the excessive solder (good product) has to be made defective. Is.

  As described above, according to the appearance inspection apparatus according to the first embodiment, it is possible to determine the quality of the inspection work by performing data processing by program control of a preset sequence based on one imaging data, There is no need to switch lighting. Further, the imaging operation is executed without stopping at the inspection position by inputting a position signal from the stage control device 40 to the illumination control device 50 and giving a trigger signal to the color imaging device 6 and the illumination device 5 at the inspection position. As a result, the imaging time can be significantly reduced. Further, for example, a line sensor camera or the like can be used for the purpose of speeding up.

  In addition, according to the appearance inspection method according to the first embodiment, the inspection work is irradiated with inspection light having different light colors depending on the position from a plurality of positions, and the reflected light reflected by the inspection work is reflected. Since the state of the inspection work is determined from the information for each light color obtained for each imaging area of the inspection work based on the output of the color imaging device that receives light, the illumination of various states of the inspection work can be switched. The inspection can be performed without any occurrence, the occurrence of overdetection (false alarm) is suppressed, and the inspection can be performed at a high speed while maintaining a high straightness rate.

  The present invention can be modified or omitted as appropriate within the scope of the invention. For example, in the first embodiment, the difference in average luminance in the column direction (X-axis direction) has been described. However, a difference between pixel area values generated by binarization processing for each color or a combination of average luminances may be used. . In addition, the lighting device 5 is divided into four parts a to d in the circumferential direction with respect to the lighting area. Further, depending on the soldering state, without changing the number of divisions, for example, only the area a and the area b in FIG. 2 are lit, or one of the three-stage ring light sources 51, 52, 53 is illuminated. You may make it limit suitably the light source to light, such as lighting only a part.

In Embodiment 1, the illumination device 5 is a circular ring-shaped light source unit. For example, bar-type illumination or spot-type illumination is U-shaped (4 divisions), hexagon (6 divisions), octagon (8 It may be arranged as shown in FIG. Further, in the case where the light source unit has multiple stages, the number of stages is not particularly limited in Embodiment 1, but the number of stages may be four or more. The light emission color may be a light color other than R, G, and B.
Further, for example, a means for dividing the lighting area in the circumferential direction of the ring illumination and switching the lighting area in accordance with the direction of the terminal of the soldering part and the direction of drawing the pattern from the terminal, and means for imaging under each lighting condition In addition to a single captured image, a means for performing inter-image processing on an image data group may be provided.

  DESCRIPTION OF SYMBOLS 1 Board | substrate (inspection workpiece), 2 Electronic components, 2a terminal, 3 Solder fillet, 4 Conveyance stage, 5 Illumination device, 6 Color imaging device, 40 Stage control device, 50 Illumination control device, 51, 52, 53 Ring-shaped light source part 60 Information processing apparatus.

Claims (7)

  An illuminating device provided to irradiate inspection light of different light colors depending on the position from a plurality of positions, and reflected light irradiated from the illuminating device and reflected by the inspection work. A color imaging device arranged to be, and an information processing device that determines the state of the inspection work from information for each light color obtained for each imaging area of the inspection work based on an output of the color imaging device; An appearance inspection apparatus comprising:   2. The appearance inspection according to claim 1, wherein the illumination device uses a ring-shaped light source unit that is formed in a ring shape and in which light emitting elements of different light colors are arranged in a predetermined order in the circumferential direction. apparatus.   The appearance inspection apparatus according to claim 2, wherein a plurality of the ring-shaped light source portions having different outer diameters are provided concentrically.   4. The appearance inspection apparatus according to claim 2, wherein the ring-shaped light source units are arranged so that light colors at positions facing the center of the ring are different.   The information processing apparatus divides an inspection area in a captured image into a plurality of inspection areas in a predetermined direction set in advance, obtains a maximum value of average luminance of each color for each of the divided inspection areas, and calculates the maximum value. 5. The quality of the inspection work is determined based on a difference between an average luminance of a predetermined color component obtained for each inspection area and the representative value as a representative value of the inspection area. An appearance inspection apparatus according to any one of the above.   The information processing apparatus divides an inspection area in a captured image into a plurality of inspection areas in a predetermined direction set in advance, and calculates an area value of a pixel generated by binarization of each color for each of the divided inspection areas. And determining the quality of the inspection work based on a difference between an area value of a predetermined color component obtained for each inspection area and the representative value. The appearance inspection apparatus according to any one of claims 1 to 4.   The inspection work is irradiated with inspection light of different light colors depending on the position from a plurality of positions, the reflected light reflected by the inspection work is received by a color imaging device, and obtained for each imaging area of the inspection work. An appearance inspection method, wherein the state of the inspection work is determined from the information for each light color.

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