JP2008076277A - Inspection system and inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection system and an inspection method which can inspect the condition of cream solder regardless of changes over time. <P>SOLUTION: A setting section 95b sets the intensity of infrared rays irradiated by a lighting apparatus 5 on the basis of solder correlation data 96d and LED correlation data 96e. A photographing apparatus 6 can thereby detect reflected light off the substrate surface having predetermined light intensity by a pixel corresponding to a predetermined thickness of the cream solder. On the basis of an image by the photographing apparatus 6, a section of the cream solder can be detected. The condition of the cream solder can be therefore detected regardless of the changes over time of the cream solder and an infrared LED 5a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inspection apparatus and an inspection method for inspecting the state of cream solder applied on a substrate.

  Conventionally, in order to stabilize the quality of a board on which electronic components are mounted, an inspection apparatus for inspecting the state of solder has been developed.

  For example, Patent Document 1 discloses a method for inspecting a solder formed between a semiconductor device and a substrate on a substrate on which the semiconductor device is mounted. In this method, the substrate is irradiated with light having a wavelength in the infrared region, the reflected light having the wavelength in the infrared region that is transmitted through the polyimide substrate and reflected by the solder surface is detected by the camera, and the image signal data is obtained. A gray level image signal is obtained by AD conversion, and the state of solder is detected by measuring an area composed of pixels larger than a preset density value in a predetermined region.

JP 9-89536 A

  It is conceivable to apply a conventional method of irradiating a polyamide substrate after bonding, that is, after reflowing, to an inspection apparatus and inspection method for inspecting the state of cream solder applied on the substrate. That is, it is conceivable to irradiate infrared light from above the substrate on which the cream solder is applied and inspect the application state of the cream solder based on the reflected light. At this time, although infrared light is reflected on the surface of the solder particles on the surface of the cream solder, a part of the light passes through the flux and is also reflected on the electrode surface formed on the substrate surface, so the reflected light from this electrode surface is detected. By doing so, it is conceivable to inspect the internal state of the cream solder.

  However, since the characteristics of the cream solder and the infrared LED change with time, the light intensity of the reflected light from the substrate surface also varies. For example, in the case of cream solder, when exposed to the outside air, the characteristics deteriorate over time, such as the surface solidifying. This is because, for example, the flux of the cream solder that constitutes the cream solder and the solder powder deteriorate, the infrared light transmitted through the flux may be scattered or attenuated. In the case of an infrared LED, the intensity of infrared light to be output changes with the passage of time. Due to these effects, the state inside the solder cannot be detected accurately.

  Accordingly, the present invention has been made to solve the above-described problems, and a first object is to provide an inspection apparatus and inspection capable of detecting the shape of cream solder applied to a substrate regardless of changes over time. It is to provide a method. A second object is to provide an inspection apparatus and an inspection method capable of detecting the internal state of the cream solder.

  In order to solve the problems as described above, an inspection apparatus according to the present invention includes an illumination unit that irradiates infrared light having a predetermined intensity on a substrate on which cream solder is applied, and infrared light. An imaging means for imaging the substrate, a detection means for detecting the shape of the cream solder based on an image by the imaging means, and an intensity of infrared light irradiated by the illumination means, at least one of the illumination means and the cream solder And a first setting means for setting according to a change with time. Thereby, the shape of the cream solder applied on the substrate can be accurately detected regardless of changes in the illumination means and the cream solder over time.

  In the inspection apparatus, the setting unit may set the intensity of infrared light irradiated by the illumination unit using a cumulative use time from the start of use of the illumination unit as a change with time of the illumination unit. Thereby, the shape of the cream solder applied on the substrate can be accurately detected regardless of the usage time of the illumination means.

  In the above inspection apparatus, the setting means is a printing machine that prints using a mask screen to apply the cream solder to the substrate as a change over time of the cream solder, after the cream solder is newly supplied on the mask screen, You may make it set the intensity | strength of the infrared light irradiated by an illumination means using at least one among the time until the printing to the board | substrate used as a test | inspection object, and the frequency | count of printing. As a result, the shape of the cream solder that has been applied to the substrate by the printing machine is accurate regardless of the elapsed time since the cream solder was supplied on the mask screen and the number of times the cream solder has been used. Can be detected.

  In the inspection apparatus, the illuminating unit may receive power supply and irradiate infrared light, and the setting unit may set the power supply amount. As a result, the shape of the cream solder applied on the substrate can be accurately detected only by setting the power supply amount to the illumination means regardless of the aging of the illumination means and cream solder.

  The inspection apparatus further includes binarization means for binarizing an image representing the intensity distribution of infrared light reflected from the substrate with a predetermined threshold, and the detection means is based on the binarized image. Thus, the cross-sectional shape of the cream solder along the surface separated from the substrate may be detected. Thereby, the cross-sectional shape of the cream solder along the surface separated from the substrate of the cream solder applied on the substrate can be accurately detected regardless of the aging of the illumination means and the cream solder.

  The inspection apparatus further includes a second setting unit configured to set a plurality of infrared light intensities irradiated by the illumination unit according to the cream solder based on the infrared light intensity set by the setting unit, The means may detect the three-dimensional shape of the cream solder based on a plurality of images with different intensities of infrared light imaged by the imaging means. Thereby, the three-dimensional shape of the cream solder applied on the substrate can be accurately detected regardless of the temporal change of the illumination means and the cream solder.

  In the inspection apparatus, the detection unit extracts an extraction unit that extracts a boundary line between a dark part and a bright part for each image, and a calculation unit that calculates a volume of the cream solder based on the plurality of boundary lines extracted by the extraction unit. May be provided. Thereby, the volume of the cream solder applied on the substrate can be accurately detected regardless of the change over time of the illumination means and the cream solder.

  The inspection apparatus may further include determination means for determining the state of the cream solder based on the detection result by the detection means. Thereby, the state of cream solder can be accurately determined regardless of the aging of the illumination means and cream solder.

  Further, an inspection apparatus according to the present invention includes an illumination unit that irradiates a substrate coated with cream solder with infrared light having a predetermined intensity, an imaging unit that images the substrate irradiated with infrared light, Binarization means for binarizing the image by the imaging means with a predetermined threshold brightness; detection means for detecting the shape of the cream solder based on the binarized image by the binarization means; You may make it provide the setting means which sets the threshold value in a value conversion means according to a time-dependent change of at least one among an illumination means and cream solder. Thereby, the shape of the cream solder applied on the substrate can be accurately detected regardless of changes in the illumination means and the cream solder over time.

  In the inspection apparatus, the detection unit may detect a cross-sectional shape of the cream solder along a surface separated from the substrate based on the binarized image by the binarization unit. Thereby, the cross-sectional shape of the cream solder applied on the substrate can be accurately detected regardless of the aging of the lighting means and the cream solder.

  The inspection apparatus may further include determination means for determining the state of the cream solder based on the detection result by the detection means. Thereby, the state of the cream solder applied on the substrate can be accurately determined regardless of the change over time of the illumination means and the cream solder.

  An inspection method according to the present invention includes an illumination step of irradiating a substrate coated with cream solder with infrared light of a predetermined intensity, an imaging step of imaging the substrate irradiated with infrared light, Based on the image captured in the imaging step, the detection step for detecting the shape of the cream solder, and the intensity of the infrared light irradiated by the illumination step according to the temporal change of at least one of the illumination means and the cream solder And a setting step for setting. Thereby, the shape of the cream solder applied on the substrate can be accurately detected regardless of the change of the cream solder with time.

  According to the present invention, a substrate coated with solder is irradiated with infrared light having an intensity set in accordance with a change with time of cream solder, and the substrate irradiated with the infrared light is imaged. The shape of the cream solder applied on the substrate can be accurately detected regardless of the change of the cream solder over time.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of inspection equipment]
As shown in FIGS. 1 and 2, the inspection apparatus 1 according to the present embodiment is covered with a cover 10 having a substantially rectangular parallelepiped shape as a whole, and the inside of the cover 10 is a substantially rectangular parallelepiped having a hollow inside. It has the base 11 formed in the shape. As shown in FIGS. 1 to 3, such an inspection apparatus 1 includes a substrate transport unit 2, a table transport unit 3, an imaging device transport unit 4, an illumination device 5, an imaging device 6, and a display device 7. And an input device 8 and a control device 9.

  As shown in FIG. 2, the substrate transport unit 2 is provided on the base 11 and transports a printed circuit board P (hereinafter referred to as a “substrate P”) as an inspection target, and includes a pair of belt conveyors. It consists of three components arranged in the X-axis direction. Specifically, in each predetermined range on both sides of the substrate conveying direction of the inspection apparatus 1, there are loading / unloading sections 2A, 2C provided with belt conveyors 20A, 21A and 20C, 21C, which will be described later. On the table 30, it has the movable part 2B provided with the belt conveyors 20B and 21B. In the present embodiment, the transport direction (left and right direction in FIG. 2) of the substrate P is referred to as the X axis, and the direction orthogonal to the X axis on the horizontal plane (up and down direction in FIG. 2) is referred to as the Y axis direction.

  In the carry-in / carry-out sections 2A and 2C, the front conveyors 20A and 20C are fixedly provided on the base 11, while the rear conveyors 21A and 21C are movable in the Y-axis direction, and a motor (not shown) ), The conveyors 21A and 21C on the rear side move, so that the conveyor interval according to the size of the substrate P can be adjusted.

  The movable portion 2B is provided with a pair of conveyors 20B and 21B on a table 30 movable in the Y-axis direction, of which the front conveyor 20B is fixed to the table 30 and the rear conveyor 21B is attached to the table 30. On the other hand, it is supported so as to be movable in the Y-axis direction. When the rear conveyor 21B is driven by a motor (not shown), the distance between the conveyors 20B and 21B is changed, so that the size change of the substrate P can be accommodated.

  Each of the conveyors 20A, 21A, 20B, 21B, 20C, and 21C is mounted with a conveyor belt (not shown) stretched around a pulley, and the conveyors 20B and 21B of the movable portion 2B are other conveyors. When located at positions corresponding to 20A, 21A, 20C, and 21C (when the table 30 is at the front end position of the movable range), the respective conveyor belts are driven by a motor 22 provided on the table 30 in conjunction with each other. As a result, the substrate P is transported.

  By adopting such a configuration, the substrate P is carried into the inspection apparatus main body 1 from the left side of the apparatus along the conveyor of the substrate transport unit 2 and is subjected to inspection processing in the inspection work area provided in the approximate center of the base 11. After being provided, it is carried out from the right side of the apparatus to the next process (in the direction of the white arrow in the figure).

  As shown in FIG. 2, the table transport unit 3 includes a table 30 having a substantially rectangular shape in plan view, a pair of guide rails 31 fixed on the base 11 along the Y-axis direction, and a Y-axis on the base 11. A ball screw shaft 32 rotatably provided along the direction and a motor 33 to which one end of the ball screw shaft 32 is connected are provided. Here, the table 30 is movable along the guide rail 31 and has a nut portion (not shown) that engages with the ball screw shaft 32. Accordingly, the table transport unit 3 moves the table 30 along the guide rail 31 in the Y-axis direction by rotating the ball screw shaft 32 by the motor 33.

  As shown in FIG. 2, the imaging device transport unit 4 is a gate type that is erected on a base surface of the base 11 at a slightly rearward position with respect to the central portion in the front-rear direction (vertical direction in FIG. 2) of the base 11. The support base 41 is provided. The support base 41 is composed of leg columns (not shown) that stand up from both ends in the left-right direction, and a beam 42 that bridges the upper ends of the leg columns. An imaging unit 43 having an illumination device 5 and an imaging device 6 for imaging the substrate P, and a driving device 44 for moving the imaging unit 43 along the support table 41 are provided on the beam portion 42 of the support table 41. Is provided. The drive device 44 includes a motor 45 installed on the beam portion 42 of the support base 41, a ball screw shaft 46 connected to the output shaft of the motor 45 and extending in the left-right direction, and in parallel with the ball screw shaft 46. And a pair of guide rails 47 installed on the beam portion 42. Here, the imaging unit 43 is supported by a support frame 48 that is screwed onto the ball screw shaft 46. Therefore, the image pickup device transport section 4 drives the motor 45 to move the image pickup device 6 integrally with the support frame 48 in the X-axis direction along the guide rail 47.

  The illumination device 5 is composed of an illumination device that outputs infrared light, such as an infrared LED (Light Emitting Diode), and is driven by a voltage supplied from the control device 9 (hereinafter referred to as “supply voltage”). For example, as shown in FIG. 4, such an illuminating device 5 is disposed above the substrate P as the imaging unit 43 together with the imaging device 6, and is movable by the imaging device transport unit 4. Here, the infrared LED 5a constituting the illumination device 5 is installed above the substrate P so that the optical axis has 10 ° ± 6 ° with respect to an axis perpendicular to the main surface of the substrate P. As shown in FIG. 4, when a pair of infrared LEDs 5 a are provided, each may be provided symmetrically with respect to the vertical axis. Such an illuminating device 5 can output infrared light having a wavelength of 875 ± 30 nm. In addition, as shown in FIG. 4, you may make it the illuminating device 5 provide not only the infrared LED 5a but visible light LED5b which irradiates visible light.

  The imaging device 6 is composed of a CCD (Charge Coupled Device) camera or the like, and has wavelength sensitivity in the infrared region. The imaging device 6 performs imaging based on an instruction from the control device 9. For example, as shown in FIG. 4, such an imaging device 6 is disposed above the substrate P as the imaging unit 43 together with the illumination device 5 and is movable by the imaging device transport unit 4.

  The display device 7 includes a known display device such as CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), or FED (Field Emission Display), a signal tower, and the like. Such a display device 7 displays various information based on instructions from the control device 9. In the present embodiment, as shown in FIG. 1, a display 7 a provided on the side surface of the cover 10 and a signal tower 7 b protruding upward from the upper surface of the cover 10 are configured.

  The input device 8 includes a device that detects input of information from the outside, such as a keyboard, a mouse, a pointing device, a button, and a touch panel. Information detected by the input device 8 is input to the control device 9. In the present embodiment, as shown in FIG. 1, a keyboard 8a provided in the vicinity of the display 7a and a mouse 8b are configured.

  The control device 9 is a device for controlling the overall operation of the inspection apparatus 1, and as shown in FIG. 3, a drive control unit 91, an illumination control unit 92, an image processing unit 93, an I / F unit 94, a main unit, and the like. A control unit 95 and a storage unit 96 are provided.

  The drive control unit 91 drives the motor (not shown) and the motor 22 of the substrate transport unit 2, the motor 33 of the table transport unit 3, and the motor 45 of the imaging device transport unit 4 based on an instruction from the main control unit 95. It is a functional part which produces | generates and outputs the drive signal for this. Thereby, the movement of the board | substrate P, the table 30, or the imaging unit 43 is implement | achieved.

  The illumination control unit 92 is a functional unit that sets a supply voltage corresponding to the light intensity of infrared light emitted from the illumination device 5 based on an instruction from the main control unit 95 and outputs the set voltage to the illumination device 5. Thereby, the illumination device 5 outputs infrared light having a predetermined intensity.

  The image processing unit 93 issues an imaging instruction to the imaging device 6 based on an instruction from the main control unit 95, and performs A / D conversion or the like on the captured image captured by the imaging device 6 based on the instruction. A functional unit that performs image processing and outputs image data. As a result, for example, image data (hereinafter referred to as “primary image data”) in which the light intensity for each pixel is expressed in shades is generated as shown in FIG.

  The I / F unit 94 causes the display device 7 to display various types of information based on instructions from the main control unit 95. Further, various information detected by the input device 8 is sent to the main control unit 95. In addition, a printing machine 101 that prints cream solder on the board, a mounting machine 102 that mounts electronic components on the board that has been inspected by the inspection apparatus 1, and type data relating to the type of cream solder applied by the printing machine 101, cream Various types of information such as substrate data related to the shape of the substrate coated with solder and mask data related to the shape of the mask used for printing are transmitted and received.

  For example, the main control unit 95 issues an instruction to the illumination control unit 92, the image processing unit 93, the drive control unit 91, and the I / F unit 94 based on an instruction from the outside such as a user or a host computer. This is a functional unit that realizes an inspection operation for inspecting the state of cream solder printed on the substrate. The main control unit 95 causes the illumination device 5 to irradiate the condition acquisition unit 95a that acquires various conditions required for the inspection of the cream solder from the outside or the storage unit 96, and the time-dependent change of the cream solder or the illumination device 5. Cream solder is applied to the imaging device 6 and the setting unit 95b for setting the light intensity of infrared light, the number of times the substrate is imaged by the imaging device 6, the threshold value for binarization by the binarization unit 95d described later, and the like. An image pickup unit 95c for picking up the imaged substrate, a binarization unit 95d for comparing the primary image data with a predetermined threshold value and performing binarization, and the binarized image data (hereinafter referred to as “secondary image”). Extraction section 95e that extracts a boundary line (contour line) (hereinafter referred to as “tertiary image data”) between the bright part and the dark part from the “data”), and detects the cross-sectional shape of the cream solder from the secondary image data. Cross section The area calculation unit 95f to be output, the volume calculation unit 95g that calculates the volume of the cream solder based on the calculated cross-sectional area, and the quality of the cream solder is determined based on the calculated cross-sectional area or volume of the cream solder And a determination unit 95h.

  The storage unit 96 is a functional unit that stores various types of information for realizing the operation of the inspection apparatus 1. Such a storage unit 96 includes a captured image captured by the imaging device 6, primary image data generated by the image processing unit 93, secondary image data binarized by the binarization unit 95d, and an extraction unit. Image data 96a such as tertiary image data indicating boundary lines (contour lines) extracted by 95e, various conditions required for the inspection of cream solder, threshold values for creating secondary image data by the binarization unit 95d, and determination Reference information 96b regarding the threshold value for determining whether the cream solder is good or bad by the portion 95h, a determination result 96c by the determining portion 95c, solder correlation data 96d regarding the correlation between the time-dependent change of the cream solder and the light intensity of the image data, and infrared rays At least LED correlation data 96e relating to the correlation between the change over time of the LED 5a and the light intensity of the image data is stored.

  Such a control device 9 is variously connected through a calculation device such as a CPU, a memory, a storage device such as an HDD (Hard Disc Drive), a communication line such as the Internet, a LAN (Local Area Network), and a WAN (Wide Area Network). The computer includes an I / F device that transmits and receives information, and a program installed in the computer. That is, the hardware device and software cooperate to control the hardware resources by a program, and the above-described drive control unit 91, illumination control unit 92, image processing unit 93, I / F unit 94, main control. The unit 95 and the storage unit 96 are realized. Note that the program may be provided in a state of being recorded on a recording medium such as a flexible disk, a CD-ROM, a DVD-ROM, or a memory card.

[Operating principle]
Next, the operation principle of the inspection apparatus 1 according to the present embodiment will be described.

  Cream solder is composed of solder powder and flux, and the solder powder and flux are sufficiently kneaded to form a paste in which the solder powder is almost uniformly diffused in the flux. When infrared light is irradiated onto a substrate coated with such cream solder, part of the infrared light is reflected by the solder powder surface and the solder powder near the surface, but part of it reflects the flux in the cream solder. While passing through the cream solder, it reaches the electrode pad made of a metal layer and is reflected by this electrode pad. This reflected light is transmitted again through the flux F in the cream solder, and the infrared light emitted to the outside of the cream solder is detected by the imaging device 6.

  In this way, when passing through the cream solder, infrared light is scattered by the solder powder or attenuated by the flux. Therefore, the thicker the cream solder, the more the infrared light passes through the cream solder and the more components that scatter or attenuate, resulting in a weaker light intensity of the reflected light.

  For example, as shown in FIG. 5, the infrared light I <b> 1 is applied to the edge of the cream solder H with respect to the cream solder H having a substantially semicircular cross section applied on the electrode pad E of the substrate P. It is assumed that the light I2 is applied to the central portion of the cream solder H. At this time, since the distance x1 from the surface of the cream solder H through which the infrared light I1 passes to the electrode pad E is short, there are few components that scatter or attenuate, so that the light intensity of the reflected light becomes strong. On the other hand, since the distance x2 from the surface of the cream solder H that passes through the electrode pad E is long, the infrared light I2 has many components that are scattered or attenuated, so that the light intensity of the reflected light is weak.

  6 (a), 7 (a), and 8 (a), the thickness of the screen when the cream solder is printed by screen printing is set to a predetermined strength on a substrate with 50 μm, 70 μm, and 100 μm, respectively. This is a captured image when infrared light is irradiated and the substrate is imaged by the imaging device 6. FIG. 6B, FIG. 7B, and FIG. 8B show the light intensity for each pixel of the captured images in FIG. 6A to FIG. 8A in 256 gradations. The number of pixels for each gradation is shown. In FIG. 6A, FIG. 7A, and FIG. 8A, the brightness of each pixel represents the light intensity of the infrared light reflected on the substrate surface. The higher the light intensity, the more white the light. The lower the intensity, the more black it is displayed.

  As shown in FIGS. 6 (a), 7 (a), and 8 (a), the silicon constituting the substrate is displayed in black because almost no reflected light is generated because infrared light is transmitted. . The electrode pad formed on the substrate is displayed in white because it reflects infrared light.

  When the cream solder is thick (70 μm, 100 μm) as shown in FIG. 7A and FIG. 8A, the light intensity of the reflected light is weakened, so that the cream solder is displayed in black on the electrode pad. Moreover, as shown in FIG.7 (b) and FIG.8 (b), the pixel number of the brightness corresponding to the cream solder represented by the range z has increased.

  On the other hand, when the cream solder is thin as shown in FIG. 6A (50 μm), the light intensity of the reflected light is strong, and since it is displayed in white, it can hardly be distinguished from the electrode pad. As shown in FIG. 6B, the number of pixels in the range z is also reduced.

  As described above, since the light intensity of the reflected light changes depending on the thickness of the cream solder, the cross-sectional shape of the cream solder can be detected based on the intensity distribution of the reflected light, in other words, the brightness of the image. That is, it can be said that the portions of pixels having the same brightness have the same cream solder thickness because infrared light is considered to have passed through the cream solder by the same distance. Moreover, the area | region below fixed brightness can be said to be the area | region where the cream solder was apply | coated with thickness more than fixed.

  For this reason, when the cream solder applied on the substrate P has cross sections (directions perpendicular to the substrate surface) as shown in FIGS. 9A to 9C, for example, these substrates P When the substrate P is imaged by irradiating infrared light with a predetermined intensity to the images, the respective images are as shown in FIGS. 10 (a) to 10 (c). 9 and FIG. 10, the substrate P has a metal plating corresponding to the electrode pad on the entire surface, and the cream solder is applied to a predetermined range on the electrode pad. .

  Specifically, as shown in FIG. 9 (a), when cream solder a is applied in the shape of a truncated cone, infrared light is reflected in the plane area of the central portion of the truncated cone of the cream solder. The passing distance in is longer, and the passing distance in the cream solder becomes shorter as it goes from the center to the periphery. If the board | substrate p with which such cream solder a was apply | coated is imaged, this captured image will become as shown to Fig.10 (a). Specifically, the portion corresponding to the electrode pad on the outer periphery of the cream solder a is displayed brightest because infrared light does not pass through the cream solder. The portion (reference numeral e1) from the edge of the cream solder a toward the center of the cream solder a has a longer distance for infrared light to pass through the inside of the cream solder as it goes toward the center. It will be displayed dark. The central portion (symbol e2) of the cream solder a is displayed darkest because the distance that infrared light passes through the cream solder is the longest.

  On the other hand, as shown in FIG. 9B, when the cream solder b is applied thinner than the cream solder a, the distance passing through the cream solder is shortened. Therefore, as shown in FIG. 10B, the cream solder b is displayed in the image as a dark part (reference numeral f1) that is brighter than the dark part e1 shown in FIG. In the dark part f1, the center part (reference numeral f2) in which the cream solder is thicker than the edge part is displayed darker than the dark part f1 because the distance through which infrared light passes is longer.

  Further, as shown in FIG. 9C, when the bubble d exists inside the cream solder c having the shape of the truncated cone, the infrared light transmitted through the portion corresponding to the bubble d passes through the cream solder. The passing distance is shortened. When such a cream solder c is imaged, this captured image is as shown in FIG. Specifically, the portion corresponding to the electrode pad on the outer periphery of the cream solder c is displayed brightest. The distance (indicated by reference numeral g1) from the edge of the cream solder c to the center of the cream solder increases the distance that infrared light passes through the cream solder as it goes to the center. Appears dark. In particular, the portion adjacent to the center is darkest. The central part (symbol g2) having the bubble d is displayed as a dark donut-shaped dark part brighter than the part of the reference sign g1 adjacent to the central part because the distance through which the infrared light passes through the cream solder is shortened by the bubble. .

  The cross-sectional shape of the cream solder at a predetermined thickness can be detected, for example, by preparing a characteristic diagram as shown in FIG. FIG. 11 shows a plurality of infrared rays of light intensity (the light intensity output from the infrared LED 5a increases as the numbers h1 and h2 increase) with respect to the substrate coated with cream solder whose thickness is already known. Cream solder film thickness and pixel brightness when irradiated (in the characteristic diagram of FIG. 11, the image is picked up and processed by the image pickup device 6 including infrared light reflected on the substrate surface and reflection components from the cream solder surface. It is a relationship diagram with the raw brightness that has not been done. In this characteristic diagram, as the thickness of each of the curves h1 to h6 increases, the reflection component from the substrate surface decreases. When the thickness exceeds a predetermined thickness, only the reflection component from the cream solder surface is present, and each has a substantially constant brightness. It shows that it will be. In addition, as the light intensity of the infrared LED 5a as the light source increases, the light intensity of the reflected light at a predetermined thickness X increases (not only the reflection component from the substrate surface but also the reflection component from the cream solder surface). It is shown that. In FIG. 11, an alternate long and short dash line h7 indicates that the light intensity in a region below this line is a component of the surface reflected light. In other words, the light intensity in the region above the alternate long and short dash line h7 means brightness including both the reflected light from the cream solder surface and the reflected light from the electrode pad surface.

  For example, when an infrared light having an intensity corresponding to the curve h6 is irradiated and a cross section with a thickness of X is to be detected, the pixel corresponding to the cross section with the thickness X is bright based on the slope of the curve h6. It can be detected that the pixel is Y. Therefore, a cross section having a thickness X can be detected by detecting a pixel having brightness Y or a pixel having brightness lower than brightness Y. At this time, by binarizing the image data, the cross-sectional shape of the cream solder can be detected more clearly. In this case, the brightness of the pixel corresponding to the thickness to be detected is obtained based on the curves h1 to h6 corresponding to the intensity of the infrared light irradiated by the illumination device 5, and this value is used as a threshold value for image data. Perform valuation. Thereby, the secondary image data representing the cross section of the cream solder at a predetermined thickness can be acquired.

  In addition, since the film thickness that can be detected changes according to the light intensity of infrared light, the sliced thickness (height) is obtained by imaging the substrate to which cream solder is applied while changing the light intensity of infrared light. ) Can be detected. In this way, by acquiring a plurality of cross sections of the cream solder and arranging and displaying these cross sections at respective heights, the three-dimensional shape of the cream solder can be approximated and displayed. At this time, the more the number of cross-sections of the cream solder to be acquired is increased, the closer the three-dimensional shape of the cream solder can be displayed.

  As described above, the thickness of the cross section of the cream solder that can be detected from the primary image data varies depending on the threshold value for binarizing the primary image data or the light intensity of infrared light. Therefore, primary image data obtained by imaging with multiple times while changing the intensity of infrared light while fixing the threshold value for binarization, and imaging with the light intensity of irradiated infrared light fixed at a predetermined value. A plurality of secondary image data having different cross-sectional thicknesses of the cream solder can be acquired by changing a threshold value when binarizing or combining them. Therefore, the three-dimensional shape of the cream solder can be detected based on these secondary image data.

  Note that the intensity of the reflected light is proportional to the intensity of the irradiated infrared light. For example, as shown in FIG. 12, as the intensity of infrared light is increased, the intensity of reflected light is increased, so that the brightness of the pixel corresponding to the cream solder becomes brighter. Specifically, the brightness of the cream solder r on the electrode pad q increases as the intensity of infrared light increases from the image s to the image u. Therefore, even if the images have the same brightness, if the intensity of the infrared light to be irradiated is high, it can be said that the cream solder in that portion is thick.

  For this reason, the intensity of the reflected light also decreases due to a change with time of the infrared LED 5a (that is, a change in which the intensity of the infrared light decreases as the accumulated usage time after the new product starts to be used). Therefore, in the present embodiment, the intensity of the infrared light irradiated by the illumination device 5 is set according to the change with time of the infrared LED 5a. The setting of the intensity of infrared light irradiated by the illumination device 5 is as follows. A power supply line (not shown) is connected to the illumination device 5. This power supply line is connected to the infrared LED 5a via a power regulator (not shown) connected on the way. The setting unit 95b sets an increase correction value for the amount of supplied power corresponding to a change with time of the infrared LED 5a (change in which the efficiency of converting electrical energy into infrared light decreases with time). The power regulator is controlled to increase the power supplied to the infrared LED 5a. Thereby, the intensity | strength of the infrared light irradiated with the illuminating device 5 is hold | maintained at predetermined intensity | strength irrespective of the time-dependent change of infrared LED5a.

  Moreover, the light intensity of the reflected light from the substrate surface changes with the aging of the cream solder. This will be described with reference to FIG.

  As shown in FIG. 13, when the cream solder made of a mixture of the solder powder H and the flux F is irradiated with infrared light from the infrared LED 5a of the illumination device 5 on the substrate P coated on the electrode E, this infrared light is emitted. The light travels as shown by arrows ad. The infrared light indicated by the arrow a reaches the surface of the electrode pad E linearly from the surface of the cream solder, is reflected by the electrode pad E, passes straight through the flux as it is, and reaches the imaging device 6. The infrared light indicated by the arrow b is irregularly reflected by the solder powder H near the surface of the cream solder. The infrared light indicated by the arrow c passes between the solder powders H at a portion close to the surface layer of the cream solder, but is reflected by the surface of the solder powder H below that, and does not finally reach the imaging device 6. The infrared light indicated by the arrow d reaches the surface of the electrode pad E while repeating reflection on the surface of the solder powder H, and is reflected by the electrode pad E. The infrared light indicated by the arrow d includes a component that reaches the imaging device 6 while being repeatedly reflected on the surface of the solder powder H, and a component that does not finally reach the imaging device 6 due to reflection on the surface of the solder powder H. included.

  A component effective for detecting the cross-sectional shape of the cream solder, that is, the reflected light from the substrate surface is a part of the arrows a and d (components that reach the imaging device 6). Cream solder that has been adjusted at the factory and sealed in a container has been supplied to the mask screen as time elapses after the seal has been released for application to the substrate by a dispenser or printing machine. After that, as the number of times the solder paste is printed by moving the squeegee increases, the solvent in the flux evaporates, the flux itself changes in quality, or the solder powder precipitates and the solder powder becomes denser. . When such a change with time occurs, the infrared light transmitted through the flux is attenuated on the way or is irregularly reflected by the solder powder H. Therefore, the intensity of the infrared light reflected on the substrate surface and reaching the imaging device 6. Becomes lower. In such a case, the imaging device 6 cannot detect the reflected light unless the light intensity of the infrared light emitted from the infrared LED 5a is increased. Therefore, in the present embodiment, the light intensity of the infrared light irradiated by the illumination device 5 is set according to the change with time of the cream solder. That is, the increase correction value of the amount of supplied power is set so as to increase the intensity of the infrared light emitted from the infrared LED 5a in accordance with the aging of the cream solder.

[Operation of inspection equipment]
Next, with reference to FIG. 14, the inspection operation by the inspection apparatus 1 according to the present embodiment will be described.

  First, the condition acquisition unit 95a of the main control unit 95 acquires various data necessary for inspecting the state of the cream solder applied to the substrate (step S1). The various data includes, for example, substrate data related to the shape of the substrate and wiring patterns formed on the substrate, mask data related to the shape of the mask used for printing the cream solder on the substrate, and the position and order of imaging the substrate. Imaging position order data, inspection position data regarding the position on the substrate to be inspected, thickness data regarding the position in the thickness direction of the cream solder whose cross-sectional shape is to be detected, light intensity of infrared light irradiated by the illumination device 5 and Height correlation data indicating the relationship between the brightness of the pixel to be detected and the height of the cross section of the solder that can be detected, image processing selection data relating to the image processing to be selected, type data relating to the type of cream solder applied to the substrate, solder correlation data 96d , And LED correlation data 96e. These data are acquired from the storage unit 96, the printer 101, the host computer of the mounting line, and the like.

  When acquiring the inspection data, the setting unit 95b sets the intensity of the infrared light irradiated by the illumination device 5 based on the solder correlation data 96d and the LED correlation data 96e (step S2).

  The solder correlation data 96d is composed of a characteristic diagram as shown in FIG. 15, for example. FIG. 15 shows the usage time of the cream solder, that is, the replacement of the cream solder by the printing machine 101 when the substrate coated with the cream solder whose thickness is already known is irradiated with infrared light having a plurality of light intensities. 15 is a diagram showing the relationship between the continuous printing time without image and the brightness of the pixels of the image captured by the imaging device 6. In FIG. 15, the curves a1 to a6 are on the right side (the direction from the curve a1 to the curve a6). The intensity of infrared light becomes stronger as it goes to.

  For example, when the intensity of infrared light from the first imaging device 6 is a1, the light intensity of reflected light from the substrate detected by the imaging device 6 is c1. If h1 time passes from this state, the light intensity of the reflected light from a board | substrate will fall by the time-dependent change of cream solder (c2). When imaging is performed in a state where the light intensity of the reflected light is lowered, a binarization unit 95d described later performs a binarization with a predetermined threshold on the value of the light intensity of the pixel, thereby obtaining a predetermined thickness. In order to generate the secondary image data of the cross section of the cream solder, the secondary image data of the cross section of the cream solder having a predetermined thickness is generated. Therefore, the setting unit 95b sets the intensity of infrared light output from the illumination device 5 based on the characteristic diagram of FIG. For example, when the imaging device 6 detects the light intensity of the reflected light from the substrate having a value of c1 when h1 time has elapsed from the start of use of the cream solder, infrared light based on the following formula (1) Set the intensity.

a2 + (a3-a2) b / l (1)

  In the above formula (1), l represents the length of the straight line L, and b represents the length from the curve a2 to the point P on the straight line L. Further, the point P in FIG. 15 is the intersection of the h time and the light intensity c1, and the straight line L represents the distance between the curve a2 and the curve a3 passing through the point P.

  As described above, the setting unit 95b sets the intensity of infrared light output from the lighting device 5 on the basis of the solder correlation data 96d, thereby irradiating infrared light having an intensity corresponding to the time-dependent change of the cream solder. can do. The solder correlation data 96d can be generated by actually irradiating infrared light and detecting the cross section of the cream solder. The solder correlation data 96d sets the intensity of infrared light output by the illumination device 5 according to the number of times the cream solder is printed by moving the squeegee after the cream solder is newly supplied on the mask screen. You may do. In this case, instead of the characteristic diagram of FIG. 15, it is constituted by a characteristic diagram in which the horizontal axis in FIG.

  Further, the LED correlation data 96e is similar to the solder correlation data 96d described above, the continuous operation time of the infrared LED 5a when the infrared light having a predetermined intensity is irradiated onto the substrate coated with cream solder, and the imaging device. 6 is a characteristic diagram showing the relationship between the brightness of the pixels of the image captured by 6. The setting unit 95b can irradiate infrared light having an intensity corresponding to a change with time of the illuminating device 5 by setting the intensity of the infrared light output from the illuminating device 5 based on the characteristic diagram. The LED correlation data 96e can be generated by actually irradiating infrared light and detecting the cross section of the cream solder.

  The LED correlation data 96e is composed of a characteristic diagram as shown in FIG. 16, for example. In FIG. 16, the vertical axis represents the intensity of infrared light emitted from the infrared LED 5a, the horizontal axis represents the cumulative usage time since the start of the use of the new infrared LED 5a, and v1, v2,..., V6 represent the voltage values applied to the infrared LED 5a. It is. That is, the higher the voltage value, the greater the amount of power supplied to the infrared LED 5a.

  When using the new infrared LED 5a, when the power of the voltage value v1 is supplied, the emission intensity of the infrared LED 5a is r1, and when the cumulative usage time is h1, the emission intensity is r2. In order to ensure the same light emission intensity r1 even in the cumulative usage time h1, the power supplied to the illumination device 5 (here, the voltage value applied to the infrared LED 5a) is set based on the following equation (2).

v2 + (v3-v2) d / l (2)

  In the above equation (2), l is the length of the straight line L through which the distance between the curves v2 and v3 passes through the point P, d is the length from the point P to the curve v2 on the straight line L, and the point P is It represents the intersection of h time and emission intensity r1.

  As described above, the setting unit 95b sets the intensity of the infrared light output from the illumination device 5 based on the LED correlation data 96e, so that even if the infrared LED 5a changes over time, the setting unit 95b does not change. Intense infrared light can be irradiated. In FIG. 16, the infrared LED 5a may become slightly brighter than the infrared light having a predetermined intensity as the applied voltage value increases. In this case, an infrared sensor is arranged, and the detection value of the infrared sensor when using the new infrared LED 5a is set as a target value. Even when the cumulative use time increases, the infrared light from the infrared LED 5a by the infrared sensor is increased. Feedback control for changing the amount of power supplied to the infrared LED 5a, for example, a voltage value may be performed so that the detected value matches the target value as much as possible.

  In the present embodiment, the setting unit 95b sets the intensity of infrared light output from the lighting device 5 based on the solder correlation data 96d and the LED correlation data 96e described above. Specifically, for example, the setting unit 95b calculates the intensity of infrared light output from the lighting device 5 based on the LED correlation data 96e, and based on this value and the solder correlation data 96d, the lighting device. 5 sets the intensity of the infrared light output. Thereby, the infrared light of the intensity | strength according to the time-dependent change of cream solder and infrared LED5a can be irradiated.

  As described above, in order to acquire a plurality of secondary image data, imaging is performed a plurality of times by changing the light intensity of the infrared light while fixing the binarization threshold value, and the light intensity of the infrared light is fixed. There is a method of changing the threshold value for binarization of a single primary image data imaged in the same state, or a combination thereof, but in the following, infrared is used with the binarization threshold value fixed. An example will be described in which a plurality of secondary image data is acquired by performing imaging a plurality of times while changing the light intensity of light. Therefore, when the inspection condition is acquired, the setting unit 95b performs the number of times of imaging for each cream solder to be inspected based on the height correlation data, the thickness data, the solder correlation data 96d, and the LED correlation data 96e. Then, the value of the light intensity of the infrared light irradiated by the illumination device 5 is obtained. The number data and the intensity data are associated with each board to be inspected together with the imaging position order data, the inspection position data, and the image processing selection data. This associated data is referred to as inspection data for convenience.

  When the intensity of the infrared light irradiated by the illuminating device 5 is set, the imaging unit 95c drives the substrate transport unit 2 by the drive control unit 91, and carries in the substrate to which the cream solder is applied by the printing machine 101, It is arranged at a predetermined position on the table 30 (step S3). When the substrate is carried into a predetermined position, the imaging unit 95c drives the table transport unit 3 and the imaging device transport unit 4 by the drive control unit 91 based on the imaging position order data and the inspection position data, and the imaging unit 4 Is placed above the cream solder to be inspected on the substrate.

  When the imaging unit 4 is arranged above the cream solder to be inspected on the substrate, the imaging unit 95c irradiates infrared light while changing the intensity by the illumination device 5 based on the inspection data, and performs imaging. The board | substrate is imaged for every intensity | strength of the infrared light irradiated from the illuminating device 5 by the apparatus 6 (step S4). Here, the intensity of infrared light is set based on intensity data. Further, the quantity of the intensity of infrared light irradiated by the illumination device 5 and the number of times of imaging by the imaging device 6 are set based on the frequency data. As a result, a plurality of images with different light intensities of infrared light irradiated onto the substrate are captured. As described above, since the infrared light irradiated by the illumination device 5 is set based on the type correlation data 96d, the image of the imaging device 6 includes an image of reflected light from the substrate surface. Become.

  Imaging by the imaging device 6 may be performed until all the imaging positions of one substrate are imaged based on the imaging position order data. In this case, each imaging is performed based on the corresponding count data and intensity data. Further, the captured image is stored in the storage unit 96 together with the imaging position and the light intensity of the infrared light. Note that image processing is performed on the captured image by the image processing unit 93, and primary image data in which the light intensity for each pixel is expressed by shading is generated.

  When the primary image data is generated, the main control unit 95 selects one of the first to third image processing based on the selection data (step S5), and performs the selected image processing. (Steps S6-8). Each image processing will be described below.

<First image processing>
The first image processing is processing for binarizing the primary image data and calculating the cross-sectional area of the cream solder. This process will be described with reference to FIG.

  First, the binarization unit 95d applies cream solder to the primary image data generated by the imaging unit 95c and the imaged substrate in order to binarize the primary image data with a predetermined threshold. At this time, the mask data relating to the mask used by the printing press 101 is acquired (step S11). The mask data includes information on the position and shape of the mask opening, that is, the position and shape of the cream solder applied on the substrate. The mask data may be used that has been expanded by a predetermined value from the mask opening. As a result, it is possible to detect cream solder bleeding, bridges, and the like.

  When the primary image data and the mask data are acquired, the binarizing unit 95d generates the primary image data of the region corresponding to the cream solder (target shape K) for detecting the cross section by the imaging unit 95c. Cut out from the data (step S12). The position of the target shape K is specified based on the mask data, and primary image data of an area including the target shape K, for example, primary image data in which pixels are arranged in a matrix of I rows and J columns is acquired.

  When the primary image data including the target shape K is cut out, the binarizing unit 95d binarizes the primary image data with a predetermined brightness as a threshold (step S13). Here, the threshold value is set by the setting unit 95b in accordance with the thickness of the cross section of the cream solder to be acquired based on, for example, a characteristic diagram as shown in FIG. Therefore, when acquiring a plurality of secondary image data from a single primary image data imaged in a state where the light intensity of infrared light is fixed, by changing the threshold value, various values can be obtained from a single primary image data. Secondary image data of a cross section with a sufficient thickness can be acquired.

  By binarizing the primary image data with a predetermined threshold value, secondary image data as shown in FIG. 18 is generated. FIG. 18 shows secondary image data (hereinafter referred to as “regions I and J”) arranged in a matrix of I rows and J columns. The regions I and J include the target shape K. ing. In each pixel, “1” means brightness greater than or equal to the threshold, and “0” means brightness less than the threshold. That is, the boundary portion between the “1” pixel and the “0” pixel is a portion where the cream solder thickness is a predetermined thickness, and the “0” portion is a portion having a predetermined thickness or more. Therefore, the portion corresponding to the pixel of “0” means a cross section of the cream solder at a predetermined thickness. By binarizing the primary image data with the threshold value in this way, the edge of the cross-sectional shape of the cream solder becomes more detailed and the contour can be clarified, so the cross-sectional shape of the cream solder can be more clearly discriminated. can do.

  When binarization is performed, the target area K, which is the cross section of the cream solder, in the areas I and J becomes a dark part of “0”. The binarization unit 95b may cause the display device 7 to display the secondary image data of the regions I and J. Thereby, the user can recognize the cross-sectional shape of cream solder more easily. Therefore, the quality of the cream solder can also be determined by visual inspection of the user.

  The area calculation unit 95c of the main control unit 95 measures the area S of the cross section of the cream solder at a predetermined thickness by measuring the number of pixels corresponding to the dark part in the secondary image data (step S14). Specifically, the area calculation unit 95c measures the number of dark pixels in the image-converted regions I and J. Thereby, the cross-sectional area S of the cream solder in a predetermined thickness is measured. It should be noted that the cross-sectional area S of the cream solder is binarized in step S7, and the “1” pixel in the regions I and J is the dark part (data “0”) and the “0” pixel is the bright part (data). The measurement may be performed after data conversion to “1”) is performed. In this case, when the image data is displayed on the display device 7, the cross section of the cream solder is displayed bright and the other portions are displayed dark. Even if it does in this way, it will become easy to judge cream solder visually. The cross-sectional area S of the cream solder is measured by measuring the number of “1” pixels corresponding to the cross-section of the cream solder.

<Second image processing>
The second image processing is processing for detecting tertiary image data indicating a boundary line between a bright part and a dark part from the secondary image data. This process will be described with reference to FIG.

  First, the above-described first image processing is performed by the binarization unit 95d and the area calculation unit 95f (step S21).

  When the first image processing is performed, the extraction unit 95e detects a bright pixel region in the dark region included in the secondary image data (step S22). For example, in the case of the area (I, J) in FIG. 18, there is a pixel area “0” meaning a dark part inside the outermost “1” pixel representing the electrode pad and the like. There is a region of “1” pixels representing bubbles and the like inside the pixels. The extraction unit 95e detects this bright area B. Such a bright area B is detected by, for example, confirming the positional relationship between the bright area and the dark area in the area (I, J), such as changing the bright area closer to the center of the area (I, J) to the bright area B. This can be done.

  When the bright area B is detected, the extraction unit 95e converts the coordinates P1 (i, m) from the pixel area indicating the dark area to the bright area B and the pixel area indicating the dark area from the bright area B. The changing coordinate P1 (i, n) is detected (step S23). For example, in the case of the area (I, J) in FIG. 18, the column J is changed in each row I (for example, moved from the left side to the right side), and the pixel area indicating the dark portion is changed from the pixel area indicating the dark area to the bright area B in each row. The coordinates P1 (i, m) of the pixel to be detected and the coordinates P1 (i, n) of the pixel changing from the bright area B to the pixel area indicating the dark area are detected. Since the bright area B represents the bubbles in the cream solder, the coordinate P1 means the boundary between the cream solder and the bubbles.

  When the coordinate P1 is detected, the extraction unit 95e connects the coordinates P1 to obtain tertiary image data (contour line) L1 (step S24). The contour line L1 composed of the continuous coordinates P1 represents the outer edge of the bubbles in the cream solder.

  When the contour line L1 is set, the extraction unit 95e detects a dark part pixel area in the bright part area included in the secondary image data (step S25). For example, in the case of the region (I, J) in FIG. 18, “0” meaning cream solder or the like and “dark part” inside the “1” pixel of the outermost shell that means electrode pad or the like and means bright part. ”Pixel exists. The extraction unit 95e detects this dark area C. Accordingly, the dark area C includes the bright area B. Such detection of the dark area C is performed by confirming the positional relationship between the bright area and the dark area in the area (I, J), for example, making the dark area closer to the center of the area (I, J) the dark area C. be able to.

  When the dark area C is detected, the extraction unit 95e detects the coordinates P2 (i, o) of the pixel changing from the pixel area indicating the bright area to the dark area C, and the pixel area indicating the bright area from the dark area C. A pixel seating amount P2 (i, p) that changes to is detected (step S26). For example, in the case of the region (I, J) of FIG. 18, the column J is changed in each row I (for example, moved from the left side to the right side), and the pixel region indicating the bright portion is changed from each pixel to the dark region C in each row. Coordinates P2 (i, o) to be detected and coordinates P2 (i, p) changing from the dark area C to the pixel area indicating the bright area are detected. Since the dark area C represents the cream solder on the electrode pad, the coordinate P2 means the boundary between the electrode pad and the cream solder in the cross section indicated by the secondary image data.

  When the coordinate P2 is detected, the extraction unit 95e connects the coordinates P2 to obtain tertiary image data (contour lines) L2 (step S27). The contour line L2 composed of the continuous coordinates P2 represents the outer edge of the cream solder on the electrode pad.

  By performing the second image processing as described above, it is possible to clearly detect cream solder at a predetermined thickness and the outer edge of bubbles inside the cream solder.

  The area calculation unit 95f may calculate the cross-sectional area of the cream solder based on the extracted tertiary image data (contour lines) L1 and L2. In this case, the calculation can be performed by counting the pixels inside each of the contour lines L1 and L2 and taking the difference in the number of pixels on the contour line L1 from the number of pixels inside the contour line L2. Thereby, the more accurate cross-sectional area of the cream solder can be calculated.

<Third image processing>
The third image processing is processing for obtaining secondary image data and tertiary image data (contour lines) by the first image processing and the second image processing described above, and detecting the volume of the cream solder. This process will be described with reference to FIG.

  First, the volume calculation unit 95g sets the value D of the count data to 1, the bubble volume V0 in the cream solder to 0, and the cream solder volume V1 to 0 (step S31).

  When the values of D, V0, and V1 are set, the volume calculation unit 95g causes the extraction unit 95e to perform the second image processing based on the inspection data corresponding to the value of the number data (step S32). Thereby, the tertiary image data (contour lines) L1 and L2 based on the secondary image data that has been imaged D-th are calculated.

  When the second image processing is performed, the volume calculating unit 95g calculates the volume v1 of the bubble at a predetermined thickness based on the calculated contour line L1 (step S33). Specifically, first, the volume calculation unit 95g obtains an area S1 in the contour line L1. This area S1 can be calculated by counting the pixels inside the contour line L1. Next, the volume v1 is obtained from the product of the area S1 and the distance F between the secondary image data based on the previous (D-1) imaging and the secondary image data based on the current (D-1) imaging. Therefore, this volume v1 means the volume of bubbles at a thickness of distance F. When D = 1, the distance F means the distance between the substrate surface or the top of the cream solder and the secondary image data based on the D-th imaging.

  When the volume v1 is calculated, the volume calculation unit 95g calculates a cream solder volume v0 at a predetermined thickness based on the calculated contour line L2 (step S34). Specifically, first, the volume calculation unit 95g obtains an area S2 in the contour line L2. This area S2 is calculated by counting the pixels inside the contour line L2. Next, a difference S0 between S2 and S1 is obtained. This S0 represents the cross-sectional area of cream solder only. Next, the volume v0 is obtained from the product of the distance F between the previous image, that is, the secondary image data based on the (D-1) th imaging and the secondary image data based on the current time, that is, the Dth imaging, and the area S0. Therefore, this volume v0 means the volume of the cream solder at the thickness of the distance F. When D = 1, the distance F means the distance between the substrate surface or the top of the cream solder and the secondary image data based on the D-th imaging.

  When v1 and v0 are calculated, the volume calculation unit 95g sets V1 to the value obtained by adding v1 to V1, and sets V0 to the value obtained by adding v0 to V0 (step S35). As a result, the volume of the cream solder and bubbles at the thickness between the position in the height direction of the cross section of the cream solder corresponding to the value of the number data D and the substrate surface or the top of the cream solder is calculated as V1 or V0. The Rukoto.

  When V1 and V0 are updated, the volume calculation unit 95g checks whether or not the count data D is the maximum value (step S36).

  If the value of the count data D is not the maximum value (step S36: NO), the value of the count data D is incremented by 1 (step S37), and the process returns to step S32. On the other hand, when the value of the count data D is the maximum value (step S36: YES), the third image processing is ended.

  By performing the third image processing as described above, it is possible to calculate the volume of the cream solder or the bubbles inside the cream solder.

  The volume calculation unit 95g may display all the tertiary image data (contour lines) L1 and L2 extracted by the extraction unit 95e on the display device 7 in a state where they are arranged at respective heights. Thereby, since the three-dimensional shape including the internal state of the cream solder is approximated and displayed, the operator can more clearly recognize the state of the cream solder. At this time, by increasing the value of the number data, that is, acquiring a large amount of secondary image data, the three-dimensional shape of the cream solder can be displayed more closely.

<Pass / fail judgment processing>
When the cross-sectional area of cream solder, the volume of cream solder, the volume of bubbles, and the like are calculated by the first to third image processes described above, the determination unit 95h determines whether the cream solder to be inspected is good or bad. A determination process is performed (step S9). The quality determination process will be described with reference to FIG.

  First, the determination unit 95h confirms the performed image processing (Step S41). When the first or second image processing is performed (step S41: first and second image processing), the determination unit 95h determines the quality of the cream solder based on the calculated cross-sectional area of the cream solder. To do. On the other hand, when the third image processing is performed (step S41: third image processing), the determination unit 95h determines the quality of the cream solder based on the calculated cream solder and the volume of bubbles.

  When the first and second image processing is performed, the determination unit 95h determines whether or not the calculated cross-sectional area S of the cream solder is equal to or larger than the threshold value α (step S42). In this determination, for example, when the amount of applied cream solder is small or there are bubbles inside, and the cross-sectional area S is smaller than the threshold value α, the determination unit 95h determines that the area of the cream solder is a predetermined value. It is determined that it is not above. By doing so, it is possible to detect an excessive amount of cream solder or the presence of bubbles. Further, when a plurality of cross sections are detected, the determination unit 95h may perform the above determination for each cross section. In this case, the threshold value α may be set for each height of the cross section. Thereby, determination can be performed more accurately. Note that the threshold value α is set as appropriate according to the size and shape of the cream solder.

  When the cross-sectional area S of the cream solder is equal to or larger than the threshold value α (step S42: YES), the determination unit 95h drives the substrate transport unit 2 and the table transport unit 3 by the drive control unit 91 to place the substrate on the table 30 in a predetermined manner. Is carried out from the position to the outside of the inspection apparatus 1 (step S43). The board carried out to the outside of the inspection apparatus 1 is carried into the mounting machine 102 and electronic components are mounted by the mounting machine 102.

  On the other hand, when the cross-sectional area S of the cream solder is not equal to or greater than the threshold value α (step S42: NO), the determination unit 95h determines that the cream solder is defective and drives the display device 7 by the I / F unit 94. A warning operation is performed (step S44). As this warning operation, for example, a display indicating that there is a defect in cream solder can be displayed on the display 7a, or a lamp indicating a warning can be lit on the signal tower 7b. Thereby, it can prevent carrying out the board | substrate with which the defect cream solder was apply | coated.

  When the third image processing is performed, the determination unit 95h determines whether or not the calculated bubble volume V1 in the cream solder is equal to or less than a predetermined value β1 (step S45). For example, when the internal bubbles in the applied cream solder are large and the volume V1 is larger than the threshold value β1, the determination unit 95h determines that the applied cream solder is defective. Note that the threshold value β1 is set as appropriate according to the size and shape of the cream solder.

  When the volume V1 is less than or equal to the threshold β1 (step S45: YES), the determination unit 95h determines whether or not the calculated volume V0 of the cream solder is greater than or equal to the threshold β0 (step S46). For example, when the amount of applied cream solder is small and the volume V0 is smaller than the threshold value β0, the determination unit 95h determines that the applied cream solder is defective. Note that the threshold value β1 is set as appropriate according to the size and shape of the cream solder.

  When the volume V0 is equal to or larger than the threshold value β0 (step S46: YES), the determination unit 95h drives the substrate transport unit 2 and the table transport unit 3 by the drive control unit 91 to inspect the substrate from a predetermined position on the table 30. It is carried out of the apparatus 1 (step S43). The board carried out to the outside of the inspection apparatus 1 is carried into the mounting machine 102 and electronic components are mounted by the mounting machine 102.

  On the other hand, when the volume V1 is larger than the threshold value β1 (step S45: NO) or the volume V0 is smaller than the threshold value β0 (step S46: NO), the determination unit 95h determines that the cream solder is defective. Then, the display device 7 is driven by the I / F unit 94 to perform a warning operation (step S44).

  As described above, according to the present embodiment, the setting unit 95b sets the intensity of infrared light emitted from the illumination device 5 in accordance with the aging of the cream solder and the illumination device 5, so that the imaging device 6 can detect the reflected light from the substrate surface in which the pixel corresponding to the predetermined thickness of the cream solder has a predetermined light intensity. Therefore, the state of the cream solder can be detected based on the image by the imaging device 6. As a result, it is possible to detect the state of the cream solder regardless of the aging of the cream solder or the infrared LED 5a.

  Moreover, the board | substrate with which cream solder was apply | coated with the illuminating device 5 is irradiated with several infrared light of different intensity | strength, and the board | substrate with which infrared light was irradiated with the imaging device 6 is imaged for every intensity | strength of infrared light. Thus, a plurality of images having different intensities of infrared light irradiated on the substrate can be acquired, and the three-dimensional shape of the cream solder can be detected from these. For this reason, according to the state inside cream solder, it can prevent that the board | substrate with which the defect cream solder was apply | coated is carried out by carrying out a board | substrate or performing a warning. In particular, since the three-dimensional shape including the inside of the cream solder can be detected, the cross-sectional shape of the cream solder can be recognized more clearly.

  In the present embodiment, the setting unit 95b sets the intensity of infrared light output from the illumination device 5 based on both the solder correlation data 96d and the LED correlation data 96e. The intensity of infrared light may be set based on at least one of 96d and LED correlation data 96e.

  Further, in the present embodiment, a plurality of secondary image data are acquired by performing imaging a plurality of times while changing the light intensity of infrared light in a state where the binarization threshold is fixed. Changing the threshold value for binarizing one piece of primary image data captured with the light intensity of external light fixed, or combining the method of imaging multiple times and the method of changing the threshold value Thus, a plurality of secondary image data may be acquired. In these cases, the setting unit 95b causes the threshold value quantity and value used for binarization in the first image processing, or the threshold quantity and value used for binarization, the number of times of imaging, and red Inspection data in which the light intensity of external light is associated with each substrate to be inspected together with imaging position order data, inspection position data, and image processing selection data is created. Further, the setting unit 95b sets the number-of-times data D in the third image processing in the order of changing the binarization threshold or the order of changing the binarization threshold and the number of imaging. As a result, even when the threshold value for binarization is changed, or when a method of imaging a plurality of times and a method of changing the threshold value are combined, a plurality of secondary image data can be acquired. A dimensional shape or the like can be detected.

  In the present embodiment described above, the intensity of the infrared light irradiated by the illumination device 5 is set according to the time-dependent change of the cream solder and the time-dependent change of the infrared LED 5a, that is, the amount of power supplied to the infrared LED 5a. However, the illumination setting in step S2 shown in FIG. 14 may not be performed in the operation of the inspection apparatus. In this case, the predetermined brightness threshold used in step S13 in the first image processing shown in FIG. 17 may be shifted to a lower value. In this way, by performing binarization of the image data using an appropriate threshold value, the change over time of the cream solder and the change over time of the infrared LED 5a can be achieved without changing the intensity of the infrared light irradiated by the illumination device 5. Regardless, the cross-sectional shape of the cream solder along the surface separated from the substrate can be detected.

  The present invention can be applied to an inspection method and inspection apparatus for a substrate coated with cream solder.

It is a front view which shows the external appearance of the inspection apparatus of this invention. It is a top view which shows the internal structure of the test | inspection apparatus of this invention. It is a block diagram which shows the structure of the control system of the test | inspection apparatus of this invention. It is a figure which shows the structure of an imaging unit typically. It is a figure which shows typically the structure of cream solder. (A) is an image of reflected light when a substrate coated with cream solder is irradiated with infrared light on a 50 μm thick screen, and (b) is a graph showing the light intensity distribution in (a). (A) is an image of reflected light when a substrate coated with cream solder is irradiated with infrared light on a 70 μm thick screen, and (b) is a graph showing the light intensity distribution in (a). (A) is an image of reflected light when a substrate coated with cream solder is irradiated with infrared light on a screen having a thickness of 100 μm, and (b) is a graph showing the light intensity distribution in (a). (A)-(c) is a figure which shows typically the vertical cross section of cream solder. (A)-(c) is a figure which shows typically the image of reflected light when irradiating the infrared light of the same intensity | strength to FIG. 9 (a)-(c), respectively. It is a figure which shows the relationship between the thickness of cream solder, and the brightness of a pixel. It is a figure which shows the image of reflected light when changing the intensity | strength of infrared light. It is a figure explaining how the infrared light advances in cream solder. It is a flowchart which shows test | inspection operation | movement. It is a characteristic view of an example of solder correlation data. It is a characteristic view of an example of LED correlation data. It is a flowchart which shows 1st image processing. It is a figure which shows typically the binarized image data. It is a flowchart which shows a 2nd image process. It is a flowchart which shows a 3rd image process. It is a flowchart which shows a quality determination process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus, 2 ... Board | substrate conveyance part, 2A ... Carry-in part, 2B ... Movable part, 2C ... Unloading part, 3 ... Table conveyance part, 4 ... Imaging apparatus conveyance part, 5 ... Illumination device, 5a ... Infrared LED, 5b ... Visible light LED, 6 ... Imaging device, 7 ... Display device, 8 ... Input device, 9 ... Control device, 10 ... Cover, 11 ... Base, 20A, 20B, 20C, 21A, 21B, 21C ... Belt conveyor, 22 ... Motor, 30 ... Table, 31 ... Guide rail, 32 ... Ball screw shaft, 33 ... Motor, 41 ... Support, 42 ... Beam part, 43 ... Imaging unit, 44 ... Drive device, 45 ... Motor, 46 ... Ball screw Axis 47: guide rail 48 ... support frame 91 ... drive control unit 92 ... illumination control unit 93 ... image processing unit 94 ... I / F unit 95 ... main control unit 95a ... condition acquisition unit 95b ... Setting unit, 95c ... Imaging 95d, binarization unit, 95e, extraction unit, 95f, area calculation unit, 95g, volume calculation unit, 95h, determination unit, 96, storage unit, 96a, image data, 96b, reference information, 96c, pass / fail result, 96d: Solder correlation data, 96e: LED correlation data.

Claims (12)

Illumination means for irradiating infrared light of a predetermined intensity to a substrate coated with cream solder;
Imaging means for imaging the substrate irradiated with the infrared light;
Detection means for detecting the shape of the cream solder based on the image by the imaging means;
An inspection apparatus comprising: setting means for setting the intensity of infrared light irradiated by the illuminating means according to a change with time of at least one of the illuminating means and the cream solder. The said setting means sets the intensity | strength of the infrared light irradiated by the said illumination means using the accumulated use time from the use start of the said illumination means as a time-dependent change of the said illumination means. The inspection device described. The setting means is a printing machine that uses a mask screen to apply the cream solder to the substrate as a change with time of the cream solder, and after the cream solder is newly supplied on the mask screen 2. The inspection according to claim 1, wherein the intensity of infrared light irradiated by the illuminating unit is set using at least one of a time until printing on the substrate to be inspected and a number of times of printing. apparatus. The illumination means receives power supply and irradiates infrared light;
The inspection apparatus according to any one of claims 1 to 3, wherein the setting unit sets the power supply amount. Binarization means for binarizing an image representing an intensity distribution of infrared light reflected from the substrate with a predetermined threshold;
The said detection means detects the cross-sectional shape of the said cream solder along the surface spaced apart from the said board | substrate based on the binarized image. The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Inspection equipment. Based on the intensity of the infrared light set by the setting means, further comprising a second setting means for setting a plurality of infrared light intensity irradiated by the illumination means according to the cream solder,
The said detection means detects the three-dimensional shape of the said cream solder based on the several image from which the intensity | strength of the said infrared light imaged by the said imaging means differs. The any one of Claim 1 thru | or 5 characterized by the above-mentioned. The inspection apparatus according to item 1. The detection means includes
Extraction means for extracting a boundary line between a dark part and a bright part for each image;
The inspection apparatus according to claim 1, further comprising: a calculation unit that calculates a volume of the cream solder based on the plurality of boundary lines extracted by the extraction unit. The inspection apparatus according to claim 1, further comprising a determination unit that determines the state of the cream solder based on a detection result by the detection unit. Illumination means for irradiating infrared light of a predetermined intensity to a substrate coated with cream solder;
Imaging means for imaging the substrate irradiated with the infrared light;
Binarization means for binarizing the image by the imaging means with a predetermined threshold brightness;
Based on the binarized image by the binarizing means, detecting means for detecting the shape of the cream solder;
An inspection apparatus comprising: setting means for setting the threshold value in the binarization means according to a change with time of at least one of the illumination means and the cream solder. The inspection device according to claim 9, wherein the detection unit detects a cross-sectional shape of the cream solder along a surface separated from the substrate based on a binarized image by the binarization unit. The inspection apparatus according to claim 9, further comprising a determination unit that determines a state of the cream solder based on a detection result by the detection unit. An illumination step of irradiating a substrate coated with cream solder with infrared light of a predetermined intensity;
An imaging step of imaging the substrate irradiated with the infrared light;
Based on the image captured by the imaging step, a detection step for detecting the shape of the cream solder;
An inspection method comprising: a setting step of setting the intensity of infrared light irradiated in the illumination step according to a change with time of at least one of the illumination unit and the cream solder.

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