JP4597003B2 - Image acquisition method and apparatus for parts - Google Patents

Description

  The present invention relates to a component image acquisition method and apparatus for imaging an electronic component mounted on a circuit board with an imaging device and acquiring an image of the electronic component.

  In a component mounter that mounts electronic components (hereinafter simply referred to as components) on a circuit board, the components supplied from the component supply device are adsorbed by the adsorption nozzle of the adsorption head, and then the adsorption head is moved onto the component recognition camera. A part is imaged, the image is processed to detect the center and inclination of the part, and a suction deviation is calculated. Processing for detecting a component center and inclination or processing for detecting a suction deviation by processing a component image in this manner is called component recognition. The component mounter corrects the suction deviation detected by the component recognition and mounts the electronic component at a predetermined position on the board.

  In order to accurately perform the above-described component recognition, it is necessary to focus on the component and image the component with a recognition camera. For this reason, in the method described in Patent Document 1 below, the part sucked by the suction nozzle is imaged by the imaging means via two 45-degree reflection mirrors. Component recognition is performed by taking the component image by moving the image pickup means up and down so that the focal point is in accordance with the amount of increase that does not cause the component to collide with the mirror.

Further, in the method described in Patent Document 2 below, component thickness data is registered in advance, and based on the registered component thickness, the surface to be measured of the component adsorbed by the mounting head is combined with the image input device. The mounting head is positioned so as to come to the focal plane, and the component recognition is performed so that the surface to be measured always matches the focal plane.
Japanese Patent Laid-Open No. 05-267892 Japanese Patent No. 2801331

However, in the method of Patent Document 1, the entire camera has to be moved in order to adjust the focal length. Therefore, there is a problem that the weight of the conveyance unit is large, the drive unit is large, and the operation speed is slow. There was a problem that it was necessary to take measures to cope with the sliding movement of the cables of the.
Further, in the method of Patent Document 2, it is necessary to change the height of each nozzle depending on the parts. In this case, unless adjustment is performed when the camera is mounted in the default state, the magnification of the lens is slightly different individually. Since there is a difference in recognition accuracy, there is a problem that it is necessary to strictly adjust when the camera is attached. In this method, the height of the suction surface of the nozzle is offset upward from the part thickness data according to the part specifications so that the bottom of the part matches the recognition height. When the thickness of the parts varies, there is a problem that the recognition height also varies.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide a component image acquisition method and apparatus capable of acquiring a focused component image regardless of the thickness of the component. To do.

The present invention
An image acquisition method of capturing an image of a component sucked by a suction nozzle with an imaging device and acquiring an image of the component,
Lower the suction nozzle from above the imaging device toward the focusing surface of the imaging device,
Detecting whether the lower surface of the component sucked by the suction nozzle has passed a surface that is a predetermined distance above the focusing surface,
After detecting that the lower surface of the component has passed the surface, the suction nozzle is further lowered by the predetermined distance and stopped, and the component is imaged at the stop position.

The present invention also provides:
An image acquisition device that captures an image of a component sucked by a suction nozzle with an imaging device and acquires an image of the component,
A position sensor having a detection surface at a predetermined distance above the focusing surface of the imaging device;
Means for lowering the suction nozzle from above the imaging device toward the focusing surface,
The suction nozzle is lowered, and after detecting that the lower surface of the component has passed the detection surface, the suction nozzle is further lowered by the predetermined distance and stopped, and the component is imaged at the stop position.

  In the present invention, a part can be imaged regardless of the thickness of the part by aligning the imaged surface (bottom surface or bottom surface) of the part with the in-focus surface of the imaging apparatus. Therefore, it is possible to always obtain a focused component image and improve the component recognition accuracy.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

  FIG. 1 shows an outline of a component mounting apparatus, in which a mounting head 1 having a plurality of suction nozzles 1a is attached to an X-axis gantry 2 so as to be movable in the X-axis direction. The X-axis gantry 2 is attached to the Y-axis gantry 3 so that it can move in the Y-axis direction. As a result, the mounting head 1 can move in the X and Y directions, the electronic component supplied from the component supply device 5 is sucked by the suction nozzle 1a, and the sucked component is mounted on the circuit board 6. A recognition device 4 for recognizing the posture of the component sucked by the suction nozzle 1a is fixed to the component mounting apparatus. Although not shown in detail in FIG. 1, a mechanism for moving the suction nozzle 1a in the Z-axis direction (vertical direction) and a mechanism for rotating around the θ axis (nozzle axis) are provided.

  FIG. 2 illustrates the configuration of the control system of the component mounter and the recognition device, and FIG. 3 illustrates the imaging unit of the recognition device.

  The component mounting apparatus has a main control device 12, and the CPU 121 controls the entire component mounting apparatus. The X axis motor 13 moves the mounting head 1 in the X axis, Y axis, and Z axis directions. The drive of the Y-axis motor 14 and the Z-axis motor 15 is controlled. Further, the driving of the θ-axis motor 16 that rotates the suction nozzle 1a around the θ-axis is controlled.

  As shown in detail in FIG. 3, an imaging device 20 having a lens 20 a such as a CCD camera or a CMOS camera is disposed at the bottom of the casing 26 of the recognition device 4. At the time of component recognition, the mounting head 1 is positioned so that the suction nozzle 1a is above the imaging device 20 and the lens 20a, and the component 30 sucked by the suction nozzle 1a is imaged by the imaging device 20. At this time, in order to illuminate the component 30, the illumination controller 122 of the main control device 12 lights the illumination device 21 and illuminates the component 30.

  The recognition device 4 includes an image processing device 11 that processes an image of the component 30 captured by the imaging device 20. In the image processing device 11, an analog image signal input from the imaging device 20 is converted into digital image data by the A / D converter 111 and stored in the image memory 112. The image processing apparatus 11 stores component data such as the shape of the component 30, component dimensions, lead width, lead pitch, and lead length, and data such as suction position and mounting position for each component. A section 115 is provided.

  The CPU 116 of the image processing apparatus 11 reads and executes the component recognition program 114 stored in the memory, processes the component image stored in the image memory 112, and calculates the component center and the component inclination. The work memory 113 is used as a work memory during the image processing.

  The image processing apparatus 11 obtains an adsorption deviation amount from the calculated center position and inclination, and transmits the deviation amount to the main control apparatus 12 via the interface 117. The main control device 12 reflects the deviation amount when driving the X-axis motor 13, the Y-axis motor 14, and the θ-axis motor 16, corrects the adsorption deviation, and mounts the component 30 on the substrate 6.

  In the present invention, at the time of the above-described component recognition, the lower surface or the bottom surface (the surface to be imaged) of the component 30 is made to coincide with the in-focus surface of the imaging device 20, so A position sensor 24 for detecting that the predetermined position has been passed is provided. The position sensor 24 receives a laser beam projector 24a that horizontally projects a band-shaped laser beam (a laser beam having a line shape and a two-dimensional spread in a band shape in the XY plane) 24c, and the laser beam. The laser projector 24 a and the laser receiver 24 b are fixed to the support bases 22 and 23 attached to the upper part of the casing 26 of the recognition device 4 by a transmission type laser sensor including the laser receiver 24 b. When the suction nozzle 1a is lowered and the component 30 sucked by the suction nozzle 1a crosses the laser beam 24c, the laser beam is blocked, and the lower surface of the laser receiver 24b passes the laser beam (blocks). Detect that

  Therefore, the projection surface on which the belt-shaped laser beam 24c is projected forms a detection surface F1 for detecting passage of the lower surface of the component. In addition, since there is a focused object plane (hereinafter referred to as a focusing plane) F2 that is conjugate to the imaging plane of the imaging apparatus 20, the distance L1 between the detection plane F1 and the focusing plane F2 is measured in advance. This is stored in, for example, the component data storage unit 115 or other storage means (not shown). When the suction nozzle 1a is lowered and the lower surface of the component 30 passes through the detection surface F1, the suction nozzle 1a is lowered by the measured distance L1 and stopped there. And a clear component image can be acquired.

  The laser emission controller 123 of the main controller 12 controls on / off of the laser emission of the laser projector 24a described above.

  With such a configuration, the imaging operation will be described with reference to FIG. 4. By driving the X-axis motor 13 and the Y-axis motor 14, the mounting head 1 moves above the component supply device 5 and sucks it. The component 30 supplied from the component supply device is adsorbed by the nozzle 1a. After the component suction, the mounting head 1 moves above the imaging device 20 and stops at a predetermined height on the imaging device 20 at a position where the axis of the suction nozzle 1a coincides with the imaging axis of the imaging device 20. (Step S1).

  Subsequently, the suction nozzle 1a is lowered by driving the Z-axis motor 15 (step S2). When the lower surface of the component 30 sucked by the suction nozzle 1a blocks the laser light 24c projected from the laser projector 24a, the laser receiver 24b detects that the lower surface of the component 30 has passed the detection surface F1. (Yes in step S3), it is returned to the main controller 12. Therefore, the main controller 12 further lowers the suction nozzle 1a by the distance L1 from the position of the detection surface, and stops the lowering of the suction nozzle 1a when the lower surface of the component 30 reaches the focusing surface F2 (steps S4 and S5). .

  At the stop position of the suction nozzle 1a, the lower surface of the component 30 is in a plane conjugate with the imaging surface of the imaging device 20, and a clear component image can be acquired, so imaging is started (step S6).

  The image processing device 11 processes the captured image of the component, calculates the center of the component and the component inclination, obtains an adsorption deviation amount, and transmits the deviation amount to the main control device 12. The main control device 12 reflects the deviation amount when driving the X-axis motor 13, the Y-axis motor 14, and the θ-axis motor 16, corrects the adsorption deviation, and mounts the component 30 on the substrate 6.

  In the first embodiment, the position sensor 24 is attached at a fixed position with respect to the recognition device 4, and the positional relationship between the imaging device and the position sensor is unchanged, but in the embodiment shown in FIG. As a position sensor, a laser sensor 40 for component recognition attached to the mounting head 1 is used.

  This laser sensor 40 is a transmission type sensor composed of a laser projector 40a for projecting a strip-shaped laser beam 40c horizontally and a laser receiver 40b for receiving the strip-shaped laser beam, and the laser projector 40a and the laser receiver 40b. Can be moved up and down by an elevating device 45 controlled by the main control device 12 along guide rails 41 a and 42 a of support plates 41 and 42 attached to the mounting head 1. When the laser projector 40a and the laser receiver 40b are at the positions indicated by the dotted lines in FIG. 5, the suction nozzle 1a is lowered to this position, and the parts adsorbed there are irradiated from the side with the belt-shaped laser light, The nozzle 1a and the component 30 are rotated around the axis. At this time, by detecting the shadow of the component with the laser receiver 40b, the center of the component and the inclination of the component can be calculated, and the component can be recognized. This component recognition is used for recognition of chip components that require relatively little mounting accuracy.

  On the other hand, when the electronic component is an IC component that requires high accuracy, component recognition by the imaging device 20 is performed. In this case, the laser sensor 40 is moved to the lower part indicated by the solid line by the lifting device 45. At this time, the projection surface F3 of the belt-like laser beam 40c projected from the laser projector 40a becomes a detection surface for detecting the passage of the lower surface of the component. That is, when the component 30 is lowered and the lower surface of the component passes the laser beam 40c, the laser receiver 40b detects the passage.

  Since the mounting head 1 stops on the imaging device 20 at a predetermined height, the laser projection surface when the laser sensor 40 moves to the illustrated lower portion, that is, the detection surface F3 The distance L2 of the focusing surface F2 of the imaging device 20 can be measured in advance. Then, the measured distance L2 is stored in the component data storage unit 115 or other storage means.

  With such a configuration, the imaging operation will be described with reference to FIG. 6. As in the first embodiment, the mounting head 1 moves upward of the imaging device 20 after the component suction, and is determined in advance on the imaging device 20. At the determined height position, the suction nozzle 1a stops at a position where the axis of the suction nozzle 1a coincides with the imaging axis of the imaging device 20 (step S10).

  Subsequently, the elevating device 45 is driven to move the laser sensor 40 to a predetermined position below the component 30 (the position indicated by the solid line in FIG. 5) (steps S11 and S12), and then the suction nozzle 1a. Is lowered (step S13). When the lower surface of the component 30 sucked by the suction nozzle 1a blocks the laser light 40c projected from the laser projector 40a, the laser receiver 40b detects that the lower surface of the component 30 has passed the detection surface F3. (Yes in step S14), the main controller 12 further lowers the suction nozzle 1a by the distance L2 from the position of the detection surface F3, and stops the lowering of the suction nozzle 1a (steps S15 and S16).

  At the stop position of the suction nozzle 1a, the lower surface of the component 30 is in a plane conjugate with the imaging surface of the imaging device 30, and a clear component image can be acquired, so imaging is started (step S17). Image processing after component imaging and mounting on a substrate are the same as in the first embodiment.

  In the embodiment shown in FIG. 7, a laser sensor 50 including a laser projector 50 a and a laser receiver 50 b is provided, and each of the laser projector 50 a and the laser receiver 50 b is vertically supported downwardly attached to the mounting head 1. It is fixed to the plates 51 and 52. The mounting position of the laser sensor 50 is determined by the model. Similarly to the laser projectors 24a and 40a, the laser projector 50a projects the belt-shaped laser light 50c horizontally, and the projection surface forms the detection surface F4.

  The mounting head 1 is stopped on the imaging device 20 at a predetermined height position, and the laser sensor 50 is fixed at a predetermined position with respect to the mounting head 1. A distance L3 between the light projecting surface (detection surface F4) and the focusing surface F2 of the imaging device 20 can be measured in advance, and the measured distance L3 is used as the component data storage unit 115 or other storage means. Store it in.

  With such a configuration, the imaging operation will be described with reference to FIG. 8. As with the first and second embodiments, the mounting head 1 moves to the upper side of the imaging device 20 after picking up the components, and moves on the imaging device 20. At a predetermined height position, the suction nozzle 1a stops at a position where the axis of the suction nozzle 1a coincides with the imaging axis of the imaging device 20 (step S20).

  Subsequently, the suction nozzle 1a is lowered (step S21), and when the lower surface of the component 30 sucked by the suction nozzle 1a blocks the laser beam 50c projected from the laser projector 50a, the laser receiver 50b is moved to the component 30. Since the main surface of the suction nozzle 1a is further lowered by the distance L3 from the position of the detection surface F4, it is detected that the lower surface of the suction surface passes through the detection surface F4 (Yes in step S22). Is stopped (steps S23 and S24).

  At the stop position of the suction nozzle 1a, the lower surface of the component 30 is in a plane conjugate with the imaging surface of the imaging device 20, and a clear component image can be acquired, so imaging is started (step S25). Image processing after component imaging and mounting on a substrate are the same as in the first embodiment.

  In each of the embodiments described above, the laser projectors 24a, 40a, and 50a project a belt-shaped laser beam, but use a projector (laser light source such as an LED) that projects one or more laser beams. Also good. In the case of a single laser beam, the detection surface is a horizontal plane including this laser beam. When a plurality of laser beams are used, each laser beam is positioned on the same horizontal plane, and that surface is used as the detection surface. . Further, a reflection type position sensor can be used instead of the transmission type position sensor.

  Moreover, in each Example mentioned above, when a detection surface is brought close to a focusing surface as much as possible and the passage of the detection surface is detected, the lowering of the suction nozzle can be stopped. Since the suction nozzle stops slightly below the detection surface due to inertia, the focusing surface may be set downward by the moving distance due to inertia so that the lowering of the suction nozzle is stopped when passage of the detection surface is detected. . However, since the movement due to inertia varies, after the passage of the detection surface is detected, based on the target movement distance (L1, L2, L3), the suction nozzle is moved so that the lower surface of each component comes to the in-focus surface. The descending is preferably feedback controlled.

It is a perspective view which shows roughly the external appearance of the principal part of the component mounting machine with which this invention is used. It is a block diagram which shows the structure of the control system in connection with component recognition of the component mounting machine. FIG. 3 is an explanatory diagram illustrating an imaging state of a component in the first embodiment. 6 is a flowchart illustrating a flow of capturing an image of a component in the first embodiment. FIG. 10 is an explanatory diagram illustrating an imaging state of a component in the second embodiment. 10 is a flowchart illustrating a flow of capturing an image of a component in the second embodiment. FIG. 10 is an explanatory diagram illustrating an imaging state of a component in Example 3. 10 is a flowchart illustrating a flow of capturing an image of a component in the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mounting head 4 Recognition apparatus 20 Imaging apparatus 21 Illumination apparatus 24a, 40a, 50a Laser projector 24b, 40b, 50b Laser receiver 24c, 40c, 50c Laser light 30 Electronic component

Claims (4)

An image acquisition method of capturing an image of a component sucked by a suction nozzle with an imaging device and acquiring an image of the component,
Lower the suction nozzle from above the imaging device toward the focusing surface of the imaging device,
Detecting whether the lower surface of the component sucked by the suction nozzle has passed a surface that is a predetermined distance above the focusing surface,
After detecting that the lower surface of the component has passed the surface, the suction nozzle is further lowered by the predetermined distance to stop, and the component is imaged at the stop position. An image acquisition device that captures an image of a component sucked by a suction nozzle with an imaging device and acquires an image of the component,
A position sensor having a detection surface at a predetermined distance above the focusing surface of the imaging device;
Means for lowering the suction nozzle from above the imaging device toward the focusing surface,
After the suction nozzle is lowered and it is detected that the lower surface of the component has passed the detection surface, the suction nozzle is further lowered by the predetermined distance and stopped, and the component is imaged at the stop position. Image acquisition device.   The component image acquisition apparatus according to claim 2, wherein the position sensor is attached to a position determined with respect to the imaging apparatus.   The component image acquisition apparatus according to claim 2, wherein the position sensor is attached to a variable position or a fixed position with respect to a mounting head on which a suction nozzle is mounted.

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