JP5427222B2 - Appearance inspection device - Google Patents

Description

  The present invention relates to an appearance inspection apparatus for inspecting the mounting state of a printed wiring board on which electronic components are mounted, and more particularly to an appearance inspection apparatus suitable for use in appearance inspection of a wiring board mounted with high density.

  Conventionally, when mounting electronic components such as ICs, LSIs, resistors and capacitors on printed wiring boards, surface mounting technology has been widely used due to recent demands for smaller, higher performance and lower cost electronic devices. ing.

  When surface-mounting an electronic component or the like on a printed wiring board, a pad on which a wiring pattern or an electronic component is mounted is first formed on a rigid printed wiring board such as glass epoxy by cream solder printing or copper foil etching. . Next, after cream solder is printed on the pad by screen printing or the like, a surface mounting component is mounted at a predetermined position by an automatic component mounting machine or the like, and reflow soldering is performed. After the manufacturing, an appearance inspection such as a mounting state and a soldering state is performed by an appearance inspection apparatus, and a circuit continuity inspection and a function check of electrical operation are performed.

  Here, in the appearance inspection of the printed wiring board on which the electronic components and the like are surface-mounted, the inspection by the automatic inspection apparatus and the inspection by the visual inspection are used in combination, and the printed wiring board which is determined to be NG by the visual inspection by the automatic inspection apparatus is visually observed. Appearance inspection is performed to check the mode of mounting failure.

  As an appearance inspection by an automatic inspection apparatus, a method using imaging data obtained by capturing a two-dimensional image from the upper part of the printed wiring board and luminance data, or a method using measurement data of the three-dimensional surface shape of the printed wiring board is known. It has been. Examples of the latter include an appearance inspection method in which a master pattern based on three-dimensional shape data of a component to be solder-mounted is compared with three-dimensional measurement data measured by a three-dimensional image sensor after component mounting (for example, Patent Document 1). See), an inspection frame surrounding a pad for printing cream solder is set and stored in advance, and a solder bridge is determined depending on whether or not the extended portion of the solder measured by three-dimensional measurement after component mounting intersects the inspection frame. There is known an appearance inspection apparatus that detects the above (for example, see Patent Document 2).

  However, these visual inspections by these automatic inspection devices are all presumed inspections, and since the threshold value for evaluating mounting defects is strictly set from the viewpoint of preventing the outflow of defective products, the printed wiring board evaluated as NG Are actually inspected by visual inspection to determine whether or not mounting defects actually occur. Visual appearance inspection is performed using an appearance visual inspection apparatus.

  The visual appearance inspection device includes a support unit that supports a printed wiring board that has been poorly mounted in the automatic inspection device, a camera that images a specific portion that has been poorly mounted in the automatic inspection device, and a camera that is poorly mounted. Moving means for moving to a location. The image captured by the camera is displayed on a monitor connected to the visual appearance inspection device. The camera includes a front camera that captures an image from the normal direction of the printed wiring board and an oblique camera that captures an image from the oblique direction of the printed wiring board.

  The visual appearance inspection apparatus specifies an inspection point to be imaged and displayed in advance by a camera using position data of a defective portion specified by the automatic inspection apparatus, and moves the camera according to the inspection point. Thereby, the inspector can easily perform an appearance inspection by confirming the inspection points displayed on the monitor.

JP-A-7-91932 JP 2004-317291 A JP 2008-191106 A

  By the way, in recent printed wiring boards, surface mounting is often performed on both sides of the board from the viewpoint of high-density mounting, so that the appearance inspection apparatus uses the outer edge of the printed wiring board on which electronic components are not mounted. Need to support. However, if the outer edge of the printed wiring board is supported, warpage may occur due to the weight of the printed wiring board and the weight of the electronic component.

  When warping occurs in the printed wiring board supported by the appearance inspection device in this way, the defective portion specified in the automatic inspection device, and the inspection point specified using the position data of the defective portion in the visual appearance inspection device, There is a possibility that a difference occurs between the first and second positions, and a portion different from the defective portion to be confirmed is captured and displayed.

  In recent printed wiring boards, miniaturized electronic components are surface-mounted with high density, so the number of defective areas to be imaged by the camera is also narrowed, so if the defective area and the inspection point are misaligned It is difficult to identify the electronic component causing the mounting failure from the display on the monitor.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an appearance inspection apparatus capable of displaying an inspection point in accordance with a defective portion and performing an appearance inspection reliably even when a printed wiring board is warped.

In order to solve the above-described problem, an appearance inspection apparatus according to the present invention includes a support unit that supports an outer edge of a wiring board on which an electronic component is mounted, an imaging device that images the electronic component to be inspected, The fan-shaped first fan that diffuses in the normal direction of the wiring board, forms a surface that exists on the surface including the normal line of the wiring board, and passes through the inspection target site set for the electronic component to be inspected. A first irradiation device that irradiates light from obliquely above; and a surface existing on a surface including the normal line of the wiring board by diffusing in a normal direction of the wiring board; A second irradiating device that irradiates the fan-shaped second light beam passing through obliquely from above, and indicates the inspection point of the wiring board by crossing the first light beam and the second light beam, The imaging device is in the normal direction of the wiring board. A first camera that captures an image and a second camera that captures an image of the wiring board obliquely from above; a surface formed by an optical axis of the second camera and a normal line of the wiring board; The first irradiation apparatus is located on the same plane as the surface formed by any one of the light beams of the second irradiation apparatus.

  According to the present invention, the intersection line between the first light beam and the second light beam is displayed as the intersection of the light rays on the wiring board. However, the intersection of the light rays reflected on the wiring board also follows along the Z axis, and is always indicated as the inspection point P of the wiring board. Thereby, according to this invention, an external appearance test | inspection can be reliably performed by catching the intersection of the light ray irradiated with an irradiation apparatus with an imaging device.

It is a perspective view which shows an external appearance inspection apparatus. It is a front view which shows an external appearance inspection apparatus. It is a perspective view which shows a support part. It is a figure which shows the structure of the apparatus main body of an imaging device. It is a perspective view which shows the structure which displays the test | inspection point P by a laser irradiation apparatus. It is a figure for demonstrating the relationship between a to-be-tested site | part and the test | inspection point P. FIG. It is a figure which shows the test | inspection point P displayed on a monitor. It is a figure which shows the state correct | amended so that the test | inspection point P might be located in the center of a monitor.

  Hereinafter, an appearance inspection apparatus to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention.

  Below, the case where this invention is applied to a visual inspection apparatus is demonstrated to an example. This appearance inspection apparatus 1 is used to visually inspect the mounting state of a printed wiring board on which various electronic components such as ICs, LSIs, resistors and capacitors are surface-mounted, and are shown in FIGS. Thus, the box-shaped outer casing 2 is provided and controlled by a control unit 3 such as a PC (not shown). The appearance inspection apparatus 1 is connected to a monitor 4 and displays a captured image on the monitor 4 so that a visual inspection by an inspector is possible.

[Outer housing]
The appearance inspection apparatus 1 includes a support unit 6 that supports the printed wiring board 5, an imaging device 7 that captures an inspection point of the printed wiring board supported by the support unit 6, and a printed wiring board. The laser irradiation apparatus 8 which shows an inspection point and the control part 3 which controls operation | movement of the whole apparatus are provided.

  The outer casing 2 is open on the front side, and the printed wiring board 5 can be taken in and out of the support portion 6 provided on the floor surface 11. The outer casing 2 is provided with an imaging device 7 on the upper side and a laser irradiation device 8 on the side. Further, the outer casing 2 is provided with illumination means (not shown) for illuminating the inside.

[Supporting part]
The support unit 6 moves the relative position between the printed circuit board 5 and the imaging device 7 by moving the support frame 12 that supports the outer edge 5 a of the printed circuit board 5 and the support frame 12 in the in-plane direction of the floor surface 11. And a stage mechanism 13 to be provided.

  As shown in FIG. 3, the support frame 12 includes a pair of long side frames 12 a and 12 b that support the long side of the printed wiring board 5, and corner blocks 14 that are provided at both ends of the long side frames 12 a and 12 b. Have The support frame 12 has two pairs of corner blocks 14 connected by connecting bars 15. Long side plates 16a and 16b are disposed on the back surfaces of the long side frames 12a and 12b. A slit 17 is formed in the long side plate 16 a provided on the front surface side of the outer housing 2 along the longitudinal direction, and a fixing pin 18 for positioning the printed wiring board 5 is inserted.

  The long side frames 12a and 12b are formed so as to face each other so as to support the lower surface of the printed wiring board 5, and thereby support the outer edge 5a of the printed wiring board 5. Further, the support frame 12 has a long side frame 12b on the back side of the outer casing 2 and a long side on the front side of the outer casing 2 as the corner blocks on both sides slide back and forth along the connecting bar 15. The printed wiring board 5 can be brought close to and away from the frame 12a, and the printed wiring board 5 is brought into contact with the left corner block 14 by sliding the fixing pin 18 along the slit 17, so that the printed wiring board 5 of any size can be obtained. Can be supported.

  The support frame 12 supports the outer edge 5a on which the electronic components of the printed wiring board 5 are not mounted from the lower side, so that the printed wiring board 5 mounted on both sides can be added to the lower mounting components. Can be supported.

  The stage mechanism 13 includes an X-axis table 13a that integrally supports the support frame 12, and a Y table 13b that supports the X-axis table so as to be movable in the Y direction. The X-axis table 13a and the Y-axis table 13b include motors that operate based on control signals. By driving these motors, the X-axis table 13a is supported in the X direction and the Y-axis table 13b is supported in the Y direction. The frame 12 is moved together.

[Imaging device]
The imaging device 7 that captures an improper mounting location of the printed wiring board 5 supported by the support frame 12 is supported on the upper side of the outer casing 2 to image an improper mounting location from above. As shown in FIG. 4, the imaging device 7 includes a front camera 20 with the camera optical axis directed in the normal direction of the printed wiring board 5 supported by the support frame 12, and the camera optical axis with respect to the printed wiring board 5. And an oblique camera 21 that is inclined obliquely. The front camera 20 and the oblique camera 21 each have a predetermined imaging lens and imaging element incorporated in a lens barrel.

The imaging device 7 is provided with an oblique camera 21 on the opposite side via the front camera 20, and the front camera 20 and the oblique camera 21 are integrated in the apparatus body 7a to constitute a camera unit. . The imaging device 7 can be rotated around the optical axis α ₁ of the front camera 20, and the mounting defects can be imaged from any direction by the oblique camera 21.

  Note that the imaging device 7 may have a focus function and a zoom function in the front camera 20 and the oblique camera 21, or does not have these functions, and a focal length for realizing a deep depth of field. Photographing may be performed using a camera having an aperture and capable of pan-focus photographing, and may be displayed with an appropriate image size by processing of the control unit 3.

The imaging device 7 has the front camera 20 in advance on an extension line of the intersection line L formed by the laser irradiation device 8 so that an intersection point of laser light indicated by the laser irradiation device 8 described later can be imaged as an inspection point P. It is designed such that the optical axis α ₁ coincides and the optical axis α ₂ of the oblique camera 21 passes on the intersection line L.

  Note that the imaging device 7 may include a plurality of oblique cameras 21. For example, the imaging device 7 can be used properly according to the inspection location by providing a pair of oblique cameras 21 including a high magnification camera and a low magnification camera. The imaging device 7 may arrange a plurality of oblique cameras 21 around the optical axis α <b> 1 of the front camera 20 at equal intervals or at irregular intervals.

[Laser irradiation equipment]
Next, the laser irradiation apparatus 8 that irradiates a laser beam indicating the inspection point of the printed wiring board 5 supported by the support frame 12 will be described. The laser irradiation device 8 is a device that irradiates a visible light laser, and irradiates a fan-shaped laser beam crossing each other onto the printed wiring board 5 obliquely from above in the device main body 7a of the imaging device 7. Laser irradiation devices 8a and 8b. The first and second laser irradiation apparatuses 8a and 8b are preferably arranged in the apparatus main body 7a so that the laser beams to be irradiated are orthogonal to each other.

  The first laser irradiation device 8 a irradiates the first laser beam that passes through the inspection target site set in advance on the printed wiring board 5 by the automatic inspection device 30. Similarly, the 2nd laser irradiation apparatus 8b irradiates the 2nd laser beam which passes the to-be-inspected site | part set on the printed wiring board 5 previously. Each of the first and second laser beams is a fan-shaped light beam that diffuses in the normal direction of the printed wiring board 5 supported by the support frame 12, and crosses each other to thereby inspect the inspection points on the printed wiring board 5. Point P as an intersection.

The inspection point P is determined based on the position data of the inspection required part by specifying the inspection required part where the mounting defect is suspected by the inspection by the automatic inspection apparatus 30 performed prior to the visual inspection by the visual inspection apparatus 1. It refers to a place that requires a visual inspection set on the printed wiring board 5 supported by the frame 12. Imaging device 7, so as to image the inspection point P, provided in advance a first position to match the optical axis alpha ₁ of the second front camera 20 in the laser beam of the intersection line on the L, the support frame 12 Is moved by the stage mechanism 13 so that the site to be inspected is positioned on the intersection line L of the first and second laser beams with reference to the position data of the site to be inspected.

  Here, as shown in FIG. 6A, if the printed wiring board 5 is not warped, the printed wiring board 5 and the image pickup device 7 are based on the position data of the site to be inspected set by the automatic inspection device 30. By setting the relative position, the inspection point P that requires visual inspection with the oblique camera 21 can be captured. However, as shown in FIG. 6B, when the printed wiring board 5 supported by the support frame 12 is warped, or as shown in FIG. 6C, the print supported by the support frame 12 is printed. When the wiring board 5 is warped, the appearance inspection apparatus 1 has the support frame 12 on the basis of the position data of the inspection required site specified by the automatic inspection apparatus 30 and the position of the inspection required area set by the automatic inspection apparatus 30. When the relative position between the supported printed wiring board 5 and the imaging device 7 is set, a deviation occurs between the image of the oblique camera 21 displayed on the monitor 4 and the actual inspection target site.

In FIG. 6 (c), to the printed circuit board 5 is cambered, the optical axis alpha ₂ oblique camera 21, captures the front of the main test site, in FIG. 6 (b), the underlying printed wiring board 5 warp to the optical axis alpha ₂ oblique camera 21 captures the tip of a main test site. As described above, when the relative position between the printed wiring board 5 and the imaging device 7 is set based on the data of the site requiring inspection set by the automatic inspection device 30, it is possible to capture the inspection point P that requires visual inspection. This is not possible, and the inspector cannot know which position of which surface mount component should be viewed. In particular, in recent years, ultra-small chip parts with a side of less than 1 mm, such as 0603 chips, are used as surface-mounted parts, and these mini-chips are mounted with high density, so check the inspection point P on the monitor. It becomes difficult.

  Therefore, in the appearance inspection apparatus 1, the laser irradiation device 8 irradiates the laser beam that passes through the inspection required site set based on the data of the inspection required site set by the automatic inspection device 30. This laser light is a fan-shaped light beam that diffuses in the normal direction of the printed wiring board 5, and crosses each other so that the crossing line L passes through the inspection site of the printed wiring board 5 in the normal direction Z. A shaft is formed (FIG. 5).

  This intersection line L is displayed on the printed wiring board 5 as an intersection of the laser beams. As shown in FIG. 7, this intersection point is printed even if the site to be inspected moves up and down according to the warp of the printed wiring board 5. The intersection of the laser beams reflected on the wiring board 5 also follows the Z axis and is always indicated as the inspection point P of the printed wiring board 5. As a result, according to the appearance inspection apparatus 1, by capturing the intersection of the laser beams irradiated by the laser irradiation apparatus 8 with the imaging apparatus 7, the inspection point P can be reliably imaged and displayed on the monitor. it can.

[Control unit]
The control unit 3 performs visual inspection by controlling each unit of the appearance inspection apparatus 1 according to the operation of the inspector, and can be configured using an information processing terminal such as a PC. The control unit 3 receives from the automatic inspection device 30 the position data of the site requiring inspection of the printed wiring board 5 that has been subject to visual inspection. Based on the position data, the controller 3 moves the stage mechanism 13 so that the site to be inspected is located on the intersection of the laser beams of the first and second laser irradiation devices 8a and 8b of the laser irradiation device 8. To adjust the position of the support frame 12.

  As a result, even when the printed wiring board 5 is warped and the region to be inspected is moved in the vertical direction according to the warp, the intersection of the laser beams of the first and second laser irradiation devices 8a and 8b is the laser. Since it moves along the intersection line L of light, that is, along the normal line direction of the printed wiring board 5, it is possible to always indicate the inspection required part of the printed wiring board 5 as the inspection point P.

  Next, the control unit 3 captures an image of the inspection target portion of the printed wiring board 5 with the front camera 20 and the oblique camera 21 of the imaging device 7 and displays an image captured by the imaging device 7 on the monitor 4. In this image, since the intersection of each laser beam of the first and second laser irradiation devices 8a and 8b is displayed as the inspection point P, the inspector can easily identify the site to be inspected by using this intersection as a mark. Inspection can be performed.

  Further, the control unit 3 may display the inspection point P at the center of the monitor 4. That is, as the printed wiring board 5 bends and the required inspection site moves in the vertical direction, the inspection point P indicating the inspection required site is also monitored in the captured image of the imaging device 7 as shown in FIG. 4 may deviate from the center, and if the warp is large, the monitor 4 may not be displayed.

  Therefore, as shown in FIG. 8, the control unit 3 controls the intersection of the laser beams of the first and second laser irradiation devices 8a and 8b to be at the center of the monitor 4, thereby making it convenient for visual inspection. Can be improved. In this control, for example, the trimming range of the original image pan-focused by the image pickup device 7 is set around the intersection of the laser beams of the first and second laser irradiation devices 8a and 8b, with a predetermined image size. This can be done by displaying on the monitor 4. Alternatively, this control gives the oblique camera 21 of the imaging device 7 a function of adjusting the angle of view and a function of searching for and detecting the intersection of the laser beams of the first and second laser irradiation devices 8a and 8b. It can also be performed by taking an image around the intersection of the laser beams.

At this time, as shown in FIG. 4, the appearance inspection apparatus 1 is arranged such that the oblique camera 21 and one of the first or second laser irradiation apparatuses 8a and 8b are directed in the same direction or face each other. and forming surface S1 and the normal line of the optical axis alpha ₂ and the printed wiring board 5 of the oblique camera 21, the first or second laser irradiation device 8a to diffuse in the normal direction of the printed circuit board 5, one of 8b The surface S2 formed by the laser beam may be positioned on the same plane.

  Thereby, as shown in FIG. 8, the laser light emitted by one of the first or second laser irradiation devices 8a and 8b is irradiated in the vertical direction in the image of the oblique camera 21 displayed on the monitor 4. Constructs the Y axis. Further, the laser beam emitted by the other of the first or second laser irradiation devices 8a and 8b is irradiated in the left-right direction in the image of the oblique camera 21 displayed on the monitor 4 to constitute the X axis. Therefore, the inspection point P is also located on the Y axis, and when the inspection point P is positioned at the center of the monitor 4, the adjustment of the image trimming range of the oblique camera 21 or the oblique use is performed along the Y axis. The angle of view of the camera 21 can be adjusted, and the adjustment can be easily performed.

[Other configurations]
In the appearance inspection apparatus 1 described above, the stage mechanism 13 that moves the support frame 12 in the X and Y directions is provided in the support unit 6. However, in the present invention, the X and Y and Z direction moving mechanisms are provided in the imaging apparatus 7. And the relative position between the printed wiring board 5 and the imaging device 7 may be moved.

  In the appearance inspection apparatus 1 described above, the intersection of the laser beams of the first and second laser irradiation apparatuses 8a and 8b of the laser irradiation apparatus 8 coincides with the optical axis of the front camera 20 of the imaging apparatus 7. As described above, both positions are fixed in advance and the support portion 6 is moved in the X and Y directions so that the site to be inspected is positioned on the crossing line of the laser light. However, in the present invention, the laser irradiation device 8 and the imaging device 7 are You may provide the moving mechanism of the X, Y, Z direction in the apparatus main body 7a incorporated.

  Further, in the appearance inspection apparatus 1 described above, the imaging apparatus and the laser irradiation apparatus 8 are incorporated into the apparatus main body 7a to form a unit. However, in the present invention, the imaging apparatus 7 and the laser irradiation apparatus 8 are separately configured and the outer casing is formed. 2 may be incorporated.

  In this case, as the laser irradiation device 8, when the first laser irradiation device 8a and the second laser irradiation device 8b are arranged so that the respective laser beams are orthogonal, a moving mechanism in the X direction and the Z direction is provided on one side, On the other hand, a moving mechanism in the Y direction and the Z direction may be provided. The first laser irradiation device 8a and the second laser irradiation device 8b can each adjust the laser irradiation angle by providing a moving mechanism in the Z direction. Therefore, even when an electronic component having a height is mounted between the inspection target site and the laser beam is shielded thereby, the laser beam can be irradiated to the inspection target site by raising the irradiation position.

In this case, the arrangement in which the optical axis alpha ₂ and the first or second laser irradiation device 8a, and the one forming surface S2 laser light is 8b is positioned on the same plane of the oblique camera 21, the imaging device 7 Can be easily configured by rotating around the optical axis of the front camera 20.

  Moreover, although the case where the appearance inspection apparatus according to the present invention is applied to a visual inspection apparatus has been described above as an example, the present invention may be applied to an automatic inspection apparatus. In this case as well, it is ensured that the site to be inspected is shown as an intersection of the laser beams of the first and second laser irradiation devices 8a and 8b, and this intersection is detected and controlled to be imaged by the oblique camera 21. It is possible to capture a site to be inspected and use this captured image and position data for visual inspection.

DESCRIPTION OF SYMBOLS 1 Appearance visual inspection apparatus, 2 outer casing, 3 control part, 4 monitor, 5 printed wiring board, 6 support part, 7 imaging device, 8 laser irradiation apparatus, 11 floor surface, 12 support frame, 13 stage mechanism, 20 front Camera, 21 oblique camera, 30 automatic inspection equipment

Claims (8)

A support portion for supporting the outer edge of the wiring board on which the electronic component is mounted;
An imaging device for imaging the electronic component to be inspected;
The fan-shaped first fan that diffuses in the normal direction of the wiring board, forms a surface that exists on the surface including the normal line of the wiring board, and passes through the inspection target site set for the electronic component to be inspected. A first irradiating device that irradiates light rays obliquely from above;
Diffusing in the normal direction of the wiring board, forming a surface existing on the surface including the normal line of the wiring board, and irradiating the fan-shaped second light beam passing through the inspection target site of the electronic component from diagonally above And a second irradiation device that
By crossing the first light beam and the second light beam, an inspection point of the wiring board is indicated,
The imaging apparatus includes a first camera that captures an image from a normal direction of the wiring board, and a second camera that captures an image of the wiring board from obliquely above,
The surface formed by the optical axis of the second camera and the normal line of the wiring board is located on the same plane as the surface formed by any one of the light beams of the second irradiation device in the first irradiation device. Appearance inspection device.   The first and second irradiation devices and the imaging device are arranged so that an optical axis of the first camera and an intersection line of the first light beam and the second light beam coincide with each other. The visual inspection apparatus according to claim 1.   The visual inspection apparatus according to claim 2, further comprising a moving member that moves the support portion in an in-plane direction of the wiring board. A monitor that captures an image captured by the imaging device;
The visual inspection apparatus according to claim 1, further comprising a control unit configured to control the monitor image so as to display an intersection of the first light beam and the second light beam in accordance with a center of the monitor.   The appearance inspection apparatus according to claim 1, further comprising moving means for moving the first irradiation apparatus and the second irradiation apparatus in a normal direction of the wiring board.   The visual inspection apparatus according to claim 6, further comprising a moving unit that moves the first irradiation device and the second irradiation device in an in-plane direction of the wiring board.   The visual inspection apparatus according to claim 1, wherein the first irradiation device and the second irradiation device are arranged so that the first light beam and the second light beam are orthogonal to each other.   The visual inspection apparatus according to claim 1, further comprising a moving unit configured to move the imaging device in all or part of an in-plane direction of the wiring board and a normal direction of the wiring board.

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