JP4660309B2 - Electronic component mounting equipment - Google Patents

Description

  The present invention relates to an electronic component mounting apparatus, and more particularly to an electronic component mounting apparatus that can reduce the time required for image recognition by a camera.

  In general, in an electronic component mounting apparatus, it is necessary to accurately mount an electronic component sucked and held by a suction nozzle mounted on a mounting head at a predetermined position on a substrate fixed at a predetermined position.

  Therefore, before mounting the component, correct the deviation from the target suction position of the component sucked by the nozzle from the component supply device or the reference position of the substrate that is positioned and fixed based on the image captured by the camera. Position correction by image recognition is performed.

  In general, the mounting head is moved in the X direction by an X-axis frame (X driving means), and is moved in the Y direction integrally with the X-axis frame by a Y-axis frame (Y driving means). It is possible to move to.

  Therefore, in the image recognition when the position of the component is corrected, the mounting head is moved by the X-axis frame and the Y-axis frame, and the component sucked and held by the nozzle is moved onto the fixed camera installed at a predetermined position. After that, the mounting head moved by the XY axis frames arrives at the command coordinates and waits for a settling time until it stops, and then imaging by the camera is started.

  Similarly, when a reference mark on a substrate is imaged by a substrate recognition camera mounted on the mounting head for correcting the position of the substrate, the mounting head moved by each XY axis frame also performs mark recognition. After waiting for the command coordinates for the camera to wait for a settling time until stopping at the command coordinates, imaging by the camera was started. In addition, the settling time used here was calculated | required by actual measurement similarly to the case of the required time of mounting operation currently disclosed by patent document 1, for example.

  Strictly speaking, the settling time until the mounting head stops at each command coordinate in the X direction and Y direction varies depending on differences in the profile of the mounting head movement distance, speed, acceleration / deceleration, etc. Therefore, settling times suitable for these combinations should be set individually, but it is not practical to cover all combinations. Therefore, conventionally, a long settling time assuming the worst case is always waited.

Japanese Patent Laid-Open No. 2003-17897

  However, the conventional method of setting the settling time according to the worst case is difficult to verify the combination of the worst case itself, and in most cases, the mounting head has already stopped at the command position (coordinates). I was often waiting for wasted time.

  Also, if there is a case where the actual settling time is longer than the worst case assumed, an image is taken even though it is not stopped at the command position. A recognition error will occur.

  The present invention has been made to solve the above-mentioned conventional problems, and an image recognition camera detects a mark on a substrate positioned at a predetermined position or a component held by a suction nozzle. It is an object of the present invention to provide an electronic component mounting apparatus that can shorten the time required for recognition.

According to the present invention, a mounting head for mounting an electronic component on a substrate at a predetermined position is moved from an initial position to a command position by an X driving unit and a Y driving unit, and a substrate recognition camera mounted on the mounting head is placed on the substrate. In the electronic component mounting apparatus that recognizes a board by imaging the board mark with the camera, the mounting head reaches the command position and first overshoots, and then the command position direction The settling time is set in advance with the timing to return to the settling time, and the mounting head is moved from the initial position to reach the command position. By providing a control means for imaging the substrate mark, the above-mentioned problems are solved.

In the present invention, the mounting head for mounting the electronic component on the substrate at a predetermined position is moved from the initial position to the command position by the X driving means and the Y driving means, and is held by the suction nozzle mounted on the mounting head. In an electronic component mounting apparatus that moves a mounted electronic component onto a component recognition camera, images the electronic component with the camera, and performs component recognition, the mounting head first reaches the command position and overshoots. after, regarded as settling the timing of returning to the command position direction is preset settling regarded time, after the mounting head and allowed to reach the command position by moving from the initial position, the settling regards time At the time, the above-mentioned problem is solved in the same manner by providing control means for imaging the electronic component by the camera.

  In the present invention, the settling time may be determined on the condition that a difference between a position before imaging and a position after imaging is equal to or less than a predetermined threshold.

  In the present invention, the position of the mounting head at the time of imaging may be determined based on the position before imaging and the position after imaging. In that case, the respective positions before and after imaging are determined. Further, it may be obtained based on the output of an encoder built in the X driving means and the Y driving means.

  It is absolutely necessary that the mounting head is completely stopped at the command coordinates (command position) as a condition for imaging the parts held by the suction nozzle and the mark on the positioned substrate by the image recognition camera. Instead, it is considered that the mounting head only needs to stop at a substantially constant coordinate during the exposure time of the camera.

  Therefore, as a result of various studies by the present inventors, the following knowledge was obtained.

  When the mounting head is moved from the initial position to the command position by the X-axis frame and the Y-axis frame and stopped, the deviation of the distance from the command position reaches the normal command position as conceptually shown in FIG. After the deviation becomes zero, it overshoots to become a negative deviation, then returns to the zero deviation direction, and repeats the vibration operation before and after the command position to overshoot in the positive direction again. Stop completely at the indicated position.

Conventionally, the required time until this complete stop E was set as the settling time, but as can be seen from this figure , the settling time is temporarily almost temporarily set from A to B after returning to the command position after the first overshoot. since the state considered to be the presence, it is extremely effective if use of this to the imaging timing for the image recognition.

That is, the state of the which can be regarded as the mounting head is substantially settled temporarily fixed coordinates, since the mounting head reaches fully appreciated faster than state of stopping to E in command coordinate, the temporarily substantially settling By using the state that can be regarded as being used for the imaging timing, the imaging of the camera can be started in a shorter time than before.

Then, during the exposure time taken by the image recognition camera, the command position and the actual coordinate are managed by managing the coordinates that can be considered that the mounting head is temporarily set to a fixed coordinate temporarily based on the encoder output. And the recognition result can be corrected.

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

  FIG. 2 is a perspective view showing an outline of the electronic component mounting apparatus according to one embodiment of the present invention, with a part thereof broken.

  In this electronic component mounting apparatus, the mounting head 10 is moved in the X direction by an X-axis frame (X driving means) 12 and is integrated with the X-axis frame 12 by a Y-axis frame (Y driving means) 14 in the Y direction. The component (not shown) is sucked and held by the suction nozzle 10A that is mounted and mounted on the substrate S that has been positioned.

  In this electronic component mounting apparatus, the substrate attached to the predetermined position on the substrate S in order to correct the deviation from the reference position of the substrate S, which is conveyed by the conveying device 16 and positioned at the predetermined position, by image recognition. A substrate recognition camera 18 for imaging the mark is mounted on the mounting head 10.

  In addition, an electronic component (not shown) supplied to a predetermined position by the tape feeder 20A installed in the component supply apparatus 20 is sucked by the suction nozzle 10A, and then the target suction position (usually, the component) of the component is supplied. In order to correct the deviation from the center) by image recognition, the component recognition camera 22 is fixed at a predetermined position in a range in which the mounting head 10 (suction nozzle 10A) can move.

  FIG. 3 shows an outline of a control system of the electronic component mounting apparatus according to this embodiment.

  This control system includes an X motor 32 that drives the X-axis frame 12, a Y motor 34 that drives the Y-axis frame 14, and a rotation angle of the adsorbed components controlled by the control device 30. The board recognition camera 18 and the component recognition camera 22 are included together with a θ motor 36 that rotates the suction nozzle 10A about its axis.

  Then, the control device 30, together with the X motor driver 38, Y motor driver 40, and θ motor driver 42 that outputs drive signals to the X motor 32, Y motor 34, and θ motor 36, respectively, the board recognition camera 18 and component recognition A board video processing unit 44 and a component video processing unit 46 that respectively process image pickup data from the camera 22, and each of these drivers and image processing units perform various calculations by a control program stored in the memory 48. It is managed by the CPU 50 to be executed.

  The movement amounts of the X-axis frame 12 and the Y-axis frame 14 driven by the X motor 32 and the Y motor 34 are based on count values output from encoder counters of the X motor driver 38 and the Y motor driver 40, respectively. In addition, the CPU 50 is operated.

  In the present embodiment, when the substrate S is carried into a predetermined position of the electronic component mounting apparatus and positioned and fixed, the X-axis frame 12 and the Y-axis frame 14 are driven by the X motor 32 and the Y motor 34, respectively. The mounting head 10 at the initial position is moved in the X and Y plane directions so as to coincide with the command coordinates used as a reference when imaging by the substrate recognition camera 18 mounted on the head 10, and predetermined conditions described in detail later At the timing when the position is set, the substrate 18 is subjected to the position correction calculation based on the image obtained by imaging the mark on the substrate S by the camera 18.

  When the position correction calculation of the substrate S is completed and the component mounting position on the substrate S is determined, the mounting head 10 is moved to the pickup position (initial position) of the component supply device 20 by the X-axis frame 12 and the Y-axis frame 14. The component is sucked by the suction nozzle 10A. Thereafter, the nozzle 10 </ b> A that is picking up the component quickly moves the head 10 to a command position set above the component recognition camera 22 so as to coincide with the imaging center of the component recognition camera 22. Based on an image captured at a timing when the predetermined condition is satisfied, for example, a correction calculation is performed to correct a component suction deviation from the center of the nozzle.

  Next, the principle of position correction by image recognition will be described by taking substrate recognition for imaging a substrate mark as an example. However, in the following, the command coordinates (position) for the mounting head 10 for control will be described as command coordinates for the substrate recognition camera 18 on the image.

  Now, it is assumed that the image obtained by moving the mounting head 10 onto the substrate S and stopping at the command coordinates by the substrate recognition camera 18 is as shown in FIG. In this figure, the outer solid line rectangle is the input image G, and Gc is the image center.

  This figure shows the concept of offset used when performing image recognition correction. The center D of the plus mark in the circle is the command coordinates that the image recognition camera 18 should originally reach, and the circle indicates the board mark M. The center Mc is represented.

  Normally, when the substrate mark M is imaged by image recognition, if the reference position of the camera is the image center Gc, the control device 30 causes the X-axis frame 12 and the Y-axis so that the image center Gc matches the command coordinates. The mounting head 10 is moved by controlling the frame 14.

  Therefore, the command coordinates D: (XCOM, YCOM) should originally coincide with the image center Gc, but here it is shown that they are shifted. The deviation amount shown in the figure is calculated from the readings of the encoder counters of the X motor driver 38 and the Y motor driver 40 as feed deviations (DX, DY) by the X axis frame 12 and the Y axis frame 14. Further, in this example, it is shown that there is a deviation of (CX, CY) between the image center Gc of the camera and the mark center Mc.

  Therefore, since the correction amount of the substrate S is the deviation of the mark center Mc from the command coordinate D, it is given by the sum of (DX, DY) and (CX, CY).

  In this embodiment, imaging is performed after waiting for a settling time described below, and the relationship between the command coordinates (XCOM, YCOM) that the camera should originally reach and the encoder value representing the actual camera position before and after imaging is shown. As shown in FIG. In this figure, (X1, Y1) is the XY encoder coordinates before imaging after the settling time has elapsed, and (X2, Y2) are the XY encoder coordinates after completion of imaging, which are shown in the middle (X0, Y0). ) Are XY estimated coordinates of the substrate recognition camera 18 at the time of imaging (during exposure). In this figure, the feed deviations (DX, DY) by the X-axis frame 12 and the Y-axis frame 14 shown in FIG. 3 are also indicated by arrows.

  Next, a method for determining the optimum settling time set as the imaging timing for performing the above image recognition will be described with reference to the flowchart of FIG. In the figure, the X-axis frame, the Y-axis frame, or the drive system thereof is abbreviated as “XY axis”.

  In order to move the substrate recognition camera 18 onto the substrate mark, a command signal for moving the mounting head 10 to the command coordinates is output from the control device 30 to the X motor 32 and the Y motor 34, and the X axis frame 12, Y axis The frame 14 is driven (step 1).

  The system waits for the mounting head 10 to reach the command coordinates (step 2), and waits for a predetermined settling time (dt0) from the time of arrival (step 3). At the end of the scheduled settling time, the XY encoder coordinates (X1, Y1) immediately before imaging are read from the X and Y motor drivers 38, 40 and stored in the memory 48 (step 4), and the board mark is imaged. Is executed (step 5).

  Next, the XY encoder coordinates (X2, Y2) immediately after imaging are similarly read from the motor drivers 38 and 40 and stored (step 6).

If the absolute value of the difference between the X and Y motor encoder values before and after imaging is equal to or less than a predetermined threshold dist obtained from actual results (both NO in step 7 and step 8), after waiting for the settling time the mounting head as sufficiently even it is settling, and the processing is terminated determined該整constant predetermined time (dt0) settling deemed time (dt).

  On the other hand, if the absolute value of the difference between the motor encoder values before and after imaging is larger than the predetermined threshold dist (YES in step 7 or step 8), it is determined that the mounting head after the scheduled settling time is not sufficiently set, If the initial settling time is a sufficiently short setting, it is slightly extended and reset (step 9), and the mounting head 10 is moved to the initial position (by the X-axis frame 12 and the Y-axis frame 14). (Step 10), the processing of Step 1 to Step 10 is repeated to obtain the optimum settling time, which is determined as the settling time (dt) used for actual imaging.

  Note that the imaging of the substrate mark when determining the settling time is actually only required if the exposure timing of the camera is known. If a NOP period, that is, a period for waiting for the exposure time is provided, it is not necessary to perform actual imaging.

  When the settling time (dt) is determined by the above steps 1 to 10, it is set in the control device 30, and then the board recognition camera 18 performs imaging based on the settling time.

  Next, the calculation of the board correction amount performed based on the board mark recognition image obtained by setting the settling time in the electronic component mounting apparatus and taking an image will be described with reference to the flowchart of FIG. The following steps 11 to 16 are substantially the same as steps 1 to 6 except that the settling time (dt) preset in step 13 is used.

  First, in order to move the board recognition camera 18 onto the board mark, a command signal for moving the mounting head 10 to the command position is output from the control device 30 to the X motor 32 and the Y motor 34, and the X axis frame 12, The Y-axis frame 14 is driven (step 11). Waiting for completion of arrival of the mounting head 10 at the command position (step 12), and waiting for a predetermined settling time (dt) from the time of arrival (step 13). When the settling time has elapsed, the XY encoder coordinates (X1, Y1) immediately before imaging are read out from the corresponding motor drivers 38 and 40 and stored (step 14), and the board mark is imaged (step 15). ).

  Similarly, the XY encoder coordinates (X2, Y2) immediately after imaging are read out from the motor drivers 38 and 40 and stored (step 16).

  Next, XY coordinates (X0, Y0) during camera exposure are calculated (step 17). The estimated values (X0, Y0) of the XY coordinates during the exposure are encoder values (X1, Y1) immediately before the controller 30 issues (outputs) an imaging command for the substrate recognition camera 18 as shown in FIG. And the average value of encoder values (X2, Y2) immediately after the end of imaging. However, the encoder value itself of any XY coordinate may be used, or the encoder value of the XY coordinate during exposure may be sampled, and the average value or median value thereof may be used as the XY coordinate during exposure.

  Next, the feed deviation (DX, DY) of the mounting head by the X-axis frame 12 and the Y-axis frame 14 is calculated from the XY command coordinates (XCOM, YCOM) and the estimated values (X0, Y0) of the XY coordinates during camera exposure. At the same time (step 18), the recognition result (CX, CY) of the deviation between the image center Gc and the center Mc of the substrate mark M shown in FIG. 4 is taken based on the captured image (step 19).

  Thereafter, the deviation (δX, δY) of the center mark center Mc with respect to the XY command coordinates (XCOM, YCOM) is determined from the feed deviation (DX, DY) of the mounting head 10 and the recognition result (CX, CY) of the substrate mark. Calculate (step 20).

  In the above description, the case of substrate recognition has been described. However, by replacing the substrate recognition camera 18 with the suction nozzle 10A, the substrate with the component recognition camera 22, and the substrate mark with a component, component recognition can be performed with substantially the same processing. Can also be performed.

  According to the present embodiment described in detail above, the time required for substrate recognition can be greatly shortened and the following effects can be obtained as compared with the case of imaging after waiting for complete settling as in the prior art. it can.

  (1) By reading the encoder position of the mounting head 10 at the time of image capturing by the camera, the deviation of the actual coordinates with respect to the command coordinates can be known, so that more accurate recognition can be performed.

  (2) By collecting the scheduled settling time according to the flowchart of FIG. 6 and storing the data, if the time set as the settling time is too short, read the encoder values before and after the imaging command of the camera, An appropriate settling time can be automatically acquired from the difference.

  (3) Since the camera imaging command can be issued (output) at a timing earlier than the conventional settling time concept, the time required for the recognition of the board mark and the recognition of the components can be shortened.

  (4) Even if the actual imaging operation is not performed, the optimum settling time can be obtained by performing the movement operation using the same X-axis frame and Y-axis frame as the actual one.

  In the above embodiment, the encoder coordinate values in the X and Y directions before and after imaging are read by the encoder counter of the motor driver. However, the encoder signals may be read in electrical synchronization with the imaging signals.

  In determining the settling time, if the threshold value is exceeded in the flowchart of FIG. 6, the case where the scheduled settling time is extended in step 9 has been described. Conversely, a long time is set first. Alternatively, it may be narrowed down in the direction of shortening.

Diagram explaining settling wait time when taking an image with image recognition The perspective view which shows the outline | summary of the electronic component mounting apparatus of one Embodiment which concerns on this invention The block diagram which shows the outline | summary of the control system with which the electronic component mounting apparatus of this embodiment is provided. Explanatory drawing which shows the image of the image taken at the time of image recognition Explanatory drawing showing images of camera position before and after imaging Flow chart showing the procedure for determining settling time The flowchart which shows the correction procedure by the image recognition in this embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mounting head 10A ... Adsorption nozzle 12 ... X-axis frame 14 ... Y-axis frame 16 ... Conveyance apparatus 18 ... Board | substrate recognition camera 20 ... Component supply apparatus 22 ... Component recognition camera 30 ... Control apparatus 32 ... X motor 34 ... Y motor S …substrate

Claims (5)

The mounting head for mounting the electronic component on the board at a predetermined position is moved from the initial position to the command position by the X driving means and the Y driving means, and the board recognition camera mounted on the mounting head is placed on the board mark on the board. In an electronic component mounting apparatus that performs board recognition by imaging a board mark with the camera,
After the mounting head reaches the command position and first overshoots, the timing to return to the command position direction is set as the settling time in advance.
An electronic component mounting comprising: control means for imaging a board mark by the camera when the settling time has elapsed after the mounting head is moved from the initial position to reach the command position apparatus. The mounting head for mounting the electronic component on the substrate at a predetermined position is moved from the initial position to the command position by the X driving means and the Y driving means, and the electronic component held by the suction nozzle mounted on the mounting head is moved. In an electronic component mounting apparatus that moves onto a component recognition camera, images the electronic component with the camera, and performs component recognition.
After the mounting head reaches the command position and first overshoots, the timing to return to the command position direction is set as the settling time in advance.
An electronic component mounting comprising: a control unit that images the electronic component with the camera when the settling time has elapsed after the mounting head is moved from the initial position to reach the command position apparatus.   The electronic component mounting apparatus according to claim 1, wherein the settling time is determined on condition that a difference between a position before imaging and a position after imaging is equal to or less than a predetermined threshold.   The electronic component mounting apparatus according to claim 1, wherein the position of the mounting head at the time of imaging is determined based on a position before imaging and a position after imaging.   5. The electronic component mounting apparatus according to claim 3, wherein the positions before and after the imaging are obtained based on an output of an encoder built in the X driving unit and the Y driving unit.

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