JP2007220837A - Method and device for mounting electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for mounting an electronic component in which the electronic component can be mounted with high precision while enhancing productivity of substrate by compensating the print gap of solder surely. <P>SOLUTION: When a substrate is carried into equipment and fixed at a predetermined position (step S1), a camera is moved above a substrate mark for recognizing the substrate position formed on the substrate (S2), and then the substrate mark is imaged simultaneously with a solder mark for recognizing the solder print position printed on the substrate mark or in the vicinity thereof (S3). Based on the images thus picked up, center of gravity positions of the substrate mark and the solder mark are detected (S4, S5), and the print gap of solder for the substrate is determined by calculating the displacement n of the center of gravity position (S6). Based on the displacement n, the amount of correction is calculated on the component mounting position corresponding to the print gap of solder (S10), and the component mounting position is corrected by combining that amount of correction and other amount of correction before mounting the component (S11). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic component mounting method and apparatus for mounting an electronic component on a circuit board on which solder is printed.

  Conventionally, in an electronic component mounting apparatus, in order to accurately mount an electronic component on a circuit board (hereinafter simply referred to as a board), when the board is carried into the apparatus, the mounting position is prepared as a preparation for mounting. The board is fixed to the board, the board mark printed on the board is recognized, the position deviation of the board is detected, and the mounting position of the electronic component on the board is corrected (for example, see Patent Document 1 below).

  However, in such a configuration, the printing misalignment of the solder that prints cream solder on each electrode on the substrate is not considered. For this reason, there is a problem that the electronic component to be mounted is not correctly aligned with the solder printed on the electrode, resulting in a mounting failure.

  On the other hand, the board on which the solder pattern is printed is imaged, each electrode on the board and the position of each solder printed on the board are detected, and each electronic component is mounted based on the detection result. A configuration for correcting the position is known (see Patent Document 2).

  However, in this configuration, since all the electrodes on the board and the solder pattern printed thereon are imaged and recognized, the recognition process takes time depending on the number of parts mounted or the number of electrodes on the board. There was a problem that production tact time became long.

  On the other hand, in Patent Document 3, positioning marks are printed at a plurality of locations (for example, two locations) in the solder printing process of the substrate, the positioning marks are detected, the positional deviation of the printed pattern is obtained, and the deviation amount A configuration for correcting the component mounting position based on the above is described.

In Patent Document 4, a solder mark (paste mark) for recognizing misalignment of a solder pattern is printed on a substrate on which a substrate mark (pattern mark) is formed. A configuration is described in which the position is detected, the error amount of the position of the solder mark when the substrate mark is used as a reference is calculated, and the mounting position is corrected based on the error amount and the substrate position deviation.
JP-A-5-267899 JP 2003-92496 A Japanese Patent Publication No. 7-105635 Japanese Patent No. 3264395

  However, in the configuration of Patent Document 3, since the positional deviation of the print pattern with respect to the reference position is obtained, the positional deviation of the substrate is not taken into account. For example, when the solder printing position is slightly shifted with respect to the substrate, There has been a problem that the mounting position of the electronic component cannot be properly positioned.

  On the other hand, in the configuration of Patent Document 4, both the positional deviation of the board and the printing deviation of the solder are taken into consideration. However, imaging and recognition of the board mark for board position recognition and the solder mark for solder printing position recognition are performed. This is done separately before and after, and the positional relationship of the imaging camera with respect to each imaging position shifts due to a mechanical error between when the imaging camera is moved over the board mark and when it is moved over the solder mark. In addition to the problem that the deviation amount is added to the error at the time of correcting the mounting position, there is a problem that it takes extra time to move to the solder mark position after imaging the board mark position.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic component mounting method and apparatus capable of solving such problems, compensating for a deviation in the printing position of solder and mounting electronic components with high accuracy, and improving substrate productivity. There is to do.

The present invention for solving the above problems
An electronic component mounting method for mounting an electronic component on a substrate printed with solder,
A solder mark for recognizing a solder printing position is printed on or near a substrate mark for recognizing a substrate position formed on the substrate,
Imaging the board mark and solder mark at the same time,
The position of the board mark and the solder mark is detected from the captured image to calculate the amount of printing deviation of the solder on the board,
The component is mounted by correcting the mounting position according to the calculated printing deviation amount.

The present invention also provides:
An electronic component mounting apparatus for mounting electronic components on a printed board of solder,
An imaging means for simultaneously imaging a solder mark for solder printing position recognition printed on or near a substrate mark for substrate position recognition together with the substrate mark;
Calculation means for detecting a position of the board mark and the solder mark based on an image picked up by the image pickup means and calculating a printing deviation amount of the solder with respect to the board;
The component is mounted by correcting the mounting position according to the calculated printing deviation amount.

  In the present invention, the amount of solder printing displacement relative to the substrate is detected and the component mounting position is corrected, so that it is possible to reliably compensate for the solder printing position displacement that occurs when solder is printed on the substrate. In the present invention, since the substrate mark and the solder mark are in the same field of view of the image pickup means and images can be taken at the same time, it is possible to obtain the positional deviation amount of the substrate and the printing deviation amount of the solder relative to the substrate in a short time. The effect of being able to be obtained is obtained.

  Hereinafter, embodiments of the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically illustrating an electronic component mounting apparatus according to an embodiment of the present invention. As shown in the figure, the electronic component mounting apparatus 1 is connected to a circuit board transport path 15 extending in the left-right direction (X-axis direction) slightly rearward from the central portion and a front portion (lower side in the drawing) of the apparatus 1. A component supply unit 14 for supplying electronic components (hereinafter simply referred to as components) mounted on the substrate 10 and an X-axis moving mechanism 11 and a Y-axis moving mechanism 12 disposed above them are provided. Yes.

  The X-axis moving mechanism 11 moves the suction head unit 13 provided with a suction nozzle 13a for sucking parts in the X-axis direction, and the Y-axis moving mechanism 12 moves the X-axis moving mechanism 11 and the suction head unit 13 to the Y-axis. Move in the direction. Although not shown in FIG. 1, the suction head unit 13 includes a Z-axis moving mechanism that moves the suction nozzle 13a up and down in the vertical direction (Z-axis direction). ) Around the center of the axis).

  Further, a substrate recognition camera 17 as an imaging unit that images a substrate mark for substrate position recognition formed on the substrate 10 is attached to the suction head unit 13 together with an illumination unit (not shown) that illuminates the substrate 10. .

  In addition, on the side of the component supply unit 14, a component recognition camera 16 that captures an image of the component sucked by the suction nozzle 13a from below is disposed together with an illuminating unit (not shown) that illuminates the sucked component. In addition, although not shown in figure in order to avoid complexity, the suction head unit 13 is equipped with a laser unit for recognizing components that do not require highly accurate recognition.

  In addition, an operation monitor 18 for displaying the operation state of the apparatus is provided at the upper front of the electronic component mounting apparatus 1. Further, a control unit 19 that controls the entire apparatus and performs image processing is provided in the main body.

  FIG. 2 shows the configuration of the control system of the electronic component mounting apparatus 1. The control unit 19 in FIG. 1 includes the controller 20, the image processing device 27, the storage device 30, and the like in FIG.

  The controller 20 includes a microcomputer (CPU) that controls the entire apparatus, a RAM, a ROM, and the like. The following configurations 21 to 31 are connected to the controller 20.

  The X-axis motor 21 is a drive source for the X-axis moving mechanism 11 and moves the suction head unit 13 in the X-axis direction. The Y-axis motor 22 is a drive source for the Y-axis moving mechanism 12 and drives the X-axis moving mechanism 11 and the suction head unit 13 in the Y-axis direction, whereby the suction head unit 13 is moved in the X-axis direction and the Y-axis direction. It becomes possible to move to.

  The Z-axis motor 23 is a drive source for the Z-axis drive mechanism of the suction nozzle 13a and moves the suction nozzle 13a up and down in the Z-axis direction (height direction). The θ-axis motor 24 is a drive source for the θ-axis rotation mechanism of the suction nozzle 13a, and rotates the suction nozzle 13a around the nozzle center axis (suction axis).

  The image processing device 27 includes an A / D converter 27a, a memory 27b, and a CPU 27c. An analog image signal of the component 2 captured by the component recognition camera 16 is converted into a digital signal by the A / D converter 27a. The CPU 27c recognizes the displacement of the component center and the displacement of the suction angle with respect to the suction center of the sucked component 2 based on the component image data.

  Further, the image processing device 27 converts the image of the board mark for board position recognition and the solder mark for solder printing position recognition captured by the board recognition camera 17 into a digital signal by the A / D converter 27a. The CPU 27c detects the positions of the board mark and the solder mark based on the image data, and obtains the position deviation amount of the board and the printing deviation amount of the solder as will be described later. Then, the controller 20 corrects the mounting position of the component 2 based on each shift amount obtained from the captured images of the cameras 16 and 17, and mounts the component 2 at the correct mounting position on the substrate 10.

  The keyboard 28 and mouse 29 are used for inputting data such as component data.

  The storage device 30 is configured by a flash memory or the like, and is used to store component data input by the keyboard 28 and the mouse 29, component data supplied from a host computer (not shown), and the like.

  The display device (monitor) 31 displays component data, calculation data, the image of the component 2 captured by the component recognition camera 16, and the image of the board mark and solder mark captured by the substrate recognition camera 17 on the screen 31a.

  FIG. 3 shows an example of a stencil for printing solder on the electrodes of the substrate. In the stencil 32, a plurality of holes 33 for printing solder on the electrodes on the substrate to which the component terminals are connected are formed at positions corresponding to the respective electrodes. Further, holes 41 to 43 for printing solder marks for recognizing solder printing positions on the substrate are formed at predetermined positions on the three corners of the stencil 32, respectively. The number of solder marks may be one, but in order to increase accuracy, usually a plurality (2 to 4) of solder marks are printed, and holes corresponding to the number are formed in the stencil.

  FIG. 4 shows the substrate 10 on which solder printing has been performed using the stencil 32 of FIG. On the substrate 10, substrate marks 51 to 53 for substrate position recognition are printed in advance at predetermined positions. Solder 64 is printed on each electrode of the substrate 10 through the electrode hole 33 of the stencil 32, and solder marks 61-63 are printed through the solder mark holes 41-43. Here, the positions of the solder mark holes 41 to 43 correspond to the positions of the board marks 51 to 53, and the positions of the centers (centers of gravity) of the solder marks 61 to 63 are the board marks 51. Are printed on the substrate marks 51 to 53 so as to coincide with the positions of the centers of .about.53. Also, the holes 41 to 43 are smaller than the board marks 51 to 53, whereby the solder marks 61 to 63 are printed on the board marks 51 to 53, respectively, smaller than the board marks.

  Actually, when the solder printing is performed, the stencil 32 and the substrate 10 are misaligned. Accordingly, the solder marks 61 to 63 are printed so as to be misaligned from the substrate marks 51 to 53. Is printed out of position. In FIG. 4, the solder 64 on the electrode is shown in a state where it is not displaced in order to avoid complication.

  The component mounting operation will be described below with reference to the flowchart shown in FIG.

  Prior to the mounting operation, solder printing is performed on the substrate 10 using the stencil 32 shown in FIG. 3, and solder 64 and solder marks 61-63 are printed on the electrodes of the substrate 10 as shown in FIG.

  In step S1, the solder-printed substrate 10 is conveyed on the substrate conveyance path 15 in FIG. 1 and fixed at a predetermined position.

  In step S 2, the suction head unit 13 is moved in the X and Y axis directions by the X axis moving mechanism 11 and the Y axis moving mechanism 12, and the substrate recognition camera 17 is moved to a predetermined position facing the first substrate mark 51.

  In step S3, the substrate recognition camera 17 images the substrate mark 51 and the solder mark 61 printed thereon simultaneously, and the captured image is stored in the memory 27b. FIG. 6 shows images of the substrate mark 51 and the solder mark 61 taken.

  In steps S4 and S5, the CPU 27c of the image processing device 27 processes the captured image and detects the position (X1, Y2) of the board mark gravity center 51a and the solder mark gravity center 61a by, for example, pattern matching or detecting an edge. The position (X2, Y2) is detected, and in step S6, a deviation amount n between the positions of both center of gravity is calculated. The deviation amount n indicates the printing deviation amount (error amount) of the solder with respect to the substrate 10.

  If it is determined in step S7 that the value of the deviation n is larger than the predetermined allowable limit value m, it is determined that the solder printing is defective and the processing operation of FIG. 5 is terminated, and the component mounting operation on the board is performed. Ban. At this time, information for warning the user of defective solder printing is output.

  Although only one board mark and the solder mark printed thereon can determine the amount of printing deviation of the solder with respect to the board, the camera 17 is sequentially placed at the positions of the other board marks 52 and 53 in order to increase accuracy. Move and repeat the process of steps S3 to S7.

  When the processing is completed for all the substrate marks (step S8), the amount of solder printing deviation with respect to the substrate is finally obtained. For example, when only one set of substrate mark and solder mark is used, the amount of printing deviation is obtained as the difference between the X coordinates and the Y coordinates of the center of gravity positions of both marks. In addition, when two sets of substrate marks and solder marks are used, since the tilt correction can be performed, the average value of the difference between the barycentric coordinates (X, Y) of the two sets of substrate marks and the solder marks after the tilt correction is performed. Is the amount of printing misalignment, and when three sets of substrate marks and solder marks are used, two inclinations can be obtained. Therefore, the inclination correction is performed with the average value, and the three sets after the inclination correction is performed. The average value of the difference between the center-of-gravity coordinates (X, Y) of the board mark and the solder mark is defined as the printing deviation amount.

  When the printing deviation amount is obtained in this way, the mounting deviation amount is obtained by multiplying the printing deviation amount by a weighting coefficient (correction coefficient) k (step S10). This weighting factor can be determined according to the type of component, and is 0.5, for example. In the case of a component that requires mounting accuracy, the weighting factor is set to a value larger than 0.5. Subsequently, the mounting position is corrected with the correction amount thus obtained, and the component is mounted on the board (step S11).

  When correcting the mounting position, if there is a component adsorption deviation and a position deviation with respect to the reference position of the substrate, these deviation amounts are also corrected. The component displacement can be obtained by detecting the center position and the adsorption angle of the component by image processing of the component 2 imaged by the component recognition camera 16, and the substrate displacement can be determined by the substrate marks 51 to 53. It is calculated | required by detecting the position of. In this embodiment, the board mark and the solder mark are imaged at the same time, and the position of each mark is detected. Therefore, the printing deviation amount of the solder with respect to the substrate and the deviation amount with respect to the reference position of the substrate can be obtained in a short time. There is an advantage.

  In the above embodiment, the printing position of the solder mark is set on the board mark. However, if the board mark and the solder mark are within the same field of view of the board recognition camera 17 and can be imaged simultaneously, the position near the board mark. A solder mark may be printed on the surface.

It is the perspective view which showed the schematic structure of the whole electronic component mounting apparatus of this invention. It is the block diagram which showed the structure of the control system of the apparatus. It is a top view which shows an example of the stencil used for the solder printing of a circuit board. It is a top view which shows the circuit board which performed solder printing using the stencil. It is a flowchart figure which shows the flow of component mounting in this invention. It is explanatory drawing which shows the image of the board | substrate mark and solder mark which were imaged with the board | substrate recognition camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component mounting apparatus 2 Electronic component 10 Circuit board 11 X-axis moving mechanism 12 Y-axis moving mechanism 13 Suction head part
16 Component Recognition Camera 17 Board Recognition Camera 20 Controller 27 Image Processing Device 32 Stencil 41, 42, 43 Solder Mark Holes 51, 52, 53 Board Mark 61, 62, 63 Solder Mark 64 Solder on Electrode

Claims (4)

An electronic component mounting method for mounting an electronic component on a substrate printed with solder,
A solder mark for recognizing a solder printing position is printed on or near a substrate mark for recognizing a substrate position formed on the substrate,
Imaging the board mark and solder mark at the same time,
The position of the board mark and the solder mark is detected from the captured image to calculate the amount of printing deviation of the solder on the board,
An electronic component mounting method comprising mounting a component by correcting a mounting position in accordance with the calculated printing deviation amount.   2. The electronic component mounting method according to claim 1, wherein the calculated solder printing deviation amount is multiplied by a weighting factor, and the mounting position is corrected according to the printing deviation amount multiplied by the weighting factor. .   3. The electronic component mounting method according to claim 1, wherein the mounting operation is prohibited when a printing deviation amount of the solder exceeds a predetermined allowable limit value. 4. An electronic component mounting apparatus for mounting electronic components on a printed board of solder,
An imaging means for simultaneously imaging the solder mark for solder printing position recognition printed on or near the board mark for board position recognition together with the board mark;
Calculation means for detecting the position of the board mark and the solder mark based on the image picked up by the image pickup means and calculating the amount of printing deviation of the solder with respect to the board;
An electronic component mounting apparatus, wherein a component is mounted by correcting a mounting position according to the calculated printing deviation amount.

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