JP2012033829A - Component mounting machine and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component mounting machine to determine a mounting position of a component based on a reference position mark of a circuit board, which can easily correct displacement in a recognition position of the reference position due to tilts of optical axes from a camera with respect to a vertical direction and a difference in a height position of the reference position mark.SOLUTION: A component mounting machine includes: a recognition position displacement correction jig 25 in which two marks 26 and 27 are formed on its upper surface side with a prescribed difference of height separated from each other by a prescribed horizontal distance; and a mark camera 20 to take an image of each of the marks 26 and 27. Each position of the marks 26 and 27 is recognized from the image taken by the mark camera 20, and a displacement correction amount of recognition positions within a difference in height of the marks 26 and 27 is stored. When the mark camera 20 recognizes a position of a reference position mark 23 of a circuit board 22, displacement of the reference position mark 23 is corrected by using a difference in height between a height position of the reference position mark 23 and a reference height position, a difference in height of the two marks 26 and 27 of the recognition position displacement correction jig 25, and the displacement correction amount of recognition.

Description

  The present invention captures a reference position portion such as a reference position mark provided on a mounting surface on which a component is mounted with a camera from above, recognizes the position of the reference position portion from a captured image of the camera, and relates to the reference position portion. The present invention relates to a component mounter and an image processing method that determine a component mounting position based on the position of the component.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-72058), the distance between the camera and the reference position mark on the upper surface of the circuit board is changed due to the difference in the thickness of the circuit board, and the like. Since the positional deviation amount of the position mark changes, the accuracy of detection of the positional deviation amount of the reference position mark is deteriorated, and a camera is used that uses a measuring jig with markings to indicate the actual size at predetermined intervals. The process of changing the height position of the measurement jig located below the image stepwise and imaging the indication of the measurement jig is repeated a plurality of times, and the relationship between the dimensions per pixel and the height position of the measurement jig As the first correction data line, and when the center position of the marking changes on the captured image with the change in the height position of the measurement jig, the height position of the measurement jig and the center of the captured image And the misalignment between the center position of the marking The relationship with the number of corresponding pixels is obtained as a second correction data line, and the second positional deviation amount of the reference position mark on the captured image is obtained under different conditions of the circuit board thickness (height position) and camera tilt. Correction is performed using the first correction data line and the second correction data line.

JP 2008-72058 A

  In the above-mentioned patent document 1, even when the optical axis of the camera is tilted with respect to the vertical line, the positional deviation amount of the reference position mark on the captured image can be corrected. For this correction, two types of correction data lines ( 1st correction data line and 2nd correction data line) had to be created, and there was a problem that it took time to create two types of correction data lines.

  Therefore, the problem to be solved by the present invention is to more easily correct the deviation of the recognition position of the reference position portion due to the difference between the tilt of the optical axis of the camera from the vertical direction and the height position of the reference position portion. A component mounter and an image processing method that can be used.

  In order to solve the above-described problem, the invention according to claim 1 is directed to a camera that captures an image of a reference position provided on a mounting surface on which a component is mounted from above, and a position of the reference position from an image captured by the camera. And a component mounting machine comprising image processing means for determining the mounting position of the component with reference to the position of the reference position portion, and the inclination of the optical axis of the camera from the vertical direction and the reference position portion As a jig for correcting the deviation of the recognition position of the reference position portion due to the difference in height position, the recognition that two marks are formed on the upper surface side with a predetermined height difference and separated by a predetermined horizontal distance Using a misregistration correction jig, the image processing means captures in advance two marks of the recognition misregistration correction jig with the camera and recognizes the positions of the two marks from the captured image. One mark Data related to the amount of deviation of the recognition position in the height difference (hereinafter referred to as “correction data”) is stored in the storage means, and the reference position portion provided on the mounting surface is imaged by the camera, and the reference position portion When the position of the reference position is recognized, the height difference between the height position of the reference position portion and the reference height position, the height difference between the two marks of the recognition position deviation correction jig, and stored in the storage means The correction data is used to correct the deviation of the recognition position of the reference position portion due to the difference between the tilt of the optical axis of the camera from the vertical direction and the height position of the reference position portion.

  According to this configuration, the position of the two marks of the recognition position deviation correction jig is recognized from the captured image of the camera in advance, and correction data relating to the amount of deviation of the recognition position in the height difference between the two marks is obtained. It is possible to correct the deviation of the recognition position of the reference position portion due to the difference between the tilt of the optical axis of the camera from the vertical direction and the height position of the reference position portion. It can be corrected more easily than before.

  In this case, as described in claim 2, when the two marks of the recognition position deviation correction jig are imaged by the camera, the height position of one of the two marks is made to coincide with the reference height position. It is good to do so. Thereby, the arithmetic processing for correcting the shift of the recognition position of the reference position portion can be simplified.

  In the present invention, the two marks of the recognition misregistration correction jig may be placed in the field of view of the camera at the same time, but since the field of view of the camera for mark recognition is narrow, the two marks are within the field of view of the camera. It may not be possible to fit at the same time. In addition, if a camera using a telecentric lens is used, the displacement of the recognition position due to parallax and aberration can be eliminated. However, a camera using a telecentric lens is expensive and large, and satisfies the demands for cost reduction and space saving. I can't.

  Therefore, in the present invention, in consideration of the fact that the closer to the center of the field of view of the camera, the less the influence of the parallax and aberration of the lens becomes smaller without using a telecentric lens, When the two marks on the jig are imaged with the camera, one of the marks is positioned near the center of the field of view of the camera, the position of the one mark is recognized, and then the camera is moved in the direction of the other mark. The other mark may be horizontally moved by the true value of the horizontal distance between the two marks, and the other mark may be imaged with a camera to recognize the position of the other mark.

  In this way, if one mark is positioned near the center of the camera's field of view, the effect of the parallax and aberration of the lens is reduced and the position of one mark is accurately recognized without using a telecentric lens. In addition, the camera can be accurately moved horizontally from the one mark to the other mark, and the other mark can be taken close to the center of the field of view of the camera. As a result, the position of the other mark can also be recognized with less influence of the parallax and aberration of the lens, and correction data relating to the shift amount of the recognized position in the height difference between the two marks can be obtained with high accuracy. .

  The present invention is applicable not only when mounting components on a circuit board but also when mounting small components on top of components mounted on a circuit board (stack mounting). As in item 4, both sides of the circuit board are abutted from below with a stopper that determines the reference height position and clamped with a clamping device so that the upper surfaces of both sides of the circuit board are positioned at the reference height position. May be. Thus, if the upper surface of both sides of the circuit board is positioned at the reference height position, even if the thickness of the circuit board is different, if there is no warping of the circuit board, the height position of the reference position part on the upper surface of the circuit board. Does not change and does not shift the recognition position of the reference position portion in accordance with the reference height position. In this case, the recognition position of the reference position portion is shifted only by the vertical movement of the height position of the reference position portion due to the warp of the circuit board.

  The invention according to claim 5 describes the technical idea substantially the same as the invention of the component mounting machine according to claim 1 as an invention of an image processing method with a different category.

FIG. 1 is a block diagram schematically showing a system configuration of a component mounter according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the deviation of the recognition position of the reference position mark caused by the change in the height position of the reference position mark due to the inclination of the optical axis of the mark camera and the warp of the circuit board. FIG. 3 is a diagram for explaining the relationship between the recognition position of the reference position mark on the captured image and the original position. FIG. 4 is a diagram for explaining the positional relationship between two marks provided in the recognition position deviation correction jig and the imaging procedure for each mark. FIG. 5 is a diagram illustrating an example of a captured image of the reference mark of the recognition position deviation correction jig. FIG. 6 is a diagram illustrating an example of a captured image of the correction mark of the recognition position deviation correction jig. FIG. 7 is a diagram for explaining a method of calculating the recognition position shift amounts ΔLX and ΔLY in the height difference H between two marks from an image obtained by combining the captured image of the reference mark and the captured image of the correction mark. FIG. 8 is a diagram for explaining a process of imaging the reference position mark by moving the mark camera to a position for recognizing the reference position mark on the upper surface of the circuit board. FIG. 9 is a diagram for explaining a method of correcting the deviation of the recognition position of the reference position mark on the circuit board.

Hereinafter, an embodiment embodying a mode for carrying out the present invention will be described.
First, the system configuration of the component mounter will be described with reference to FIG.
The component mounter stores a control device 11 configured by a computer, an input device 12 such as a keyboard and a mouse, a display device 13 such as a liquid crystal display and a CRT, a component mounter control program, data for image processing, and the like. A storage device 14 (storage means), a suction nozzle moving device 15 that moves the suction nozzle in the X, Y, and Z directions, a substrate transport device 16 that transports a circuit board 22 (see FIG. 2) on which components are mounted, The clamping device 17 that clamps the circuit board 22 carried to the mounting work position by the board conveying device 16, the feeder 18 that supplies components, the parts camera 19 that images the components sucked by the suction nozzle from below, and the circuit board 22 A mark camera 20 (camera) that images the reference position mark 23 (reference position portion) on the upper surface from above, and a reference on the upper surface of the circuit board 22 The distance sensor 21 for measuring the height position of the location marks 23 has a configuration including (height position measurement unit) or the like.

  Here, the distance sensor 21 includes an optical distance sensor such as a laser distance sensor, an ultrasonic distance sensor, and the like, and is attached to the suction nozzle moving device 15 vertically downward. When the distance sensor 21 measures the height position of the reference position mark 23 on the upper surface of the circuit board 22, the suction nozzle moving device 15 moves the distance sensor 21 to a position immediately above the reference position mark 23 to thereby determine the reference position mark 23. Measure the height position.

  Further, the clamping device 17 clamps both sides of the circuit board 22 carried to the mounting work position in the component mounting machine by abutting from below with a stopper for determining a reference height position, and clamps the both sides of the circuit board 22. The upper surface is positioned at the reference height position. In this case, even if the upper surfaces of both sides of the circuit board 22 are positioned at the reference height position, if the circuit board 22 is warped, the height position of the reference position mark 23 on the upper surface of the circuit board 22 is changed from the reference height position. May shift upward or downward.

  In general, the mark camera 20 is mounted vertically downward on the suction nozzle moving device 15, but as shown in FIG. 2, the optical axis of the mark camera 20 is inclined with respect to the vertical line due to an installation error of the mark camera 20 or the like. There is a case. In such a case, when the height position of the reference position mark 23 is shifted upward or downward from the reference height position due to the warp of the circuit board 22, the center of the reference position mark 23 is made to coincide with the center of the visual field of the mark camera 20. Even if the image is taken in the state, the image of the reference position mark 23 is actually deviated from the center of the field of view of the mark camera 20 as shown in FIG. For this reason, the accuracy of the recognition position of the reference position mark 23 obtained from the captured image is lowered.

  Therefore, in this embodiment, the reference position mark is determined by the difference between the inclination of the optical axis of the mark camera 20 from the vertical direction and the height position of the reference position mark 23 using the recognition position deviation correction jig 25 shown in FIG. 23 shifts in the recognition position. The correction of the recognition position deviation is executed by the control device 11 functioning as an image processing unit in the procedure described later.

  The recognition position deviation correction jig 25 is formed in a two-step staircase shape, and a reference mark 26 is provided on the upper surface of the lower step, and a correction mark 27 is provided on the upper surface of the higher step. On the contrary, the reference mark 26 may be provided on the higher level and the correction mark 27 may be provided on the lower level. This recognition position deviation correcting jig 25 is known in that the height difference H between the two marks 26 and 27 and the horizontal distance Lb between the marks 26 and 27 are accurately measured in advance by a high-precision measuring instrument. It is the value of.

The procedure for correcting the misalignment of the recognition position of the reference position mark 23 is that the two marks 26 and 27 of the recognition position misalignment correction jig 25 are previously imaged by the mark camera 20 and the center of the two marks 26 and 27 is obtained from the captured image. The positions (X1, Y1) and (X2, Y2) are recognized, and correction data relating to the recognized positional deviation amount ΔL in the height difference H between the two marks 26, 27 is obtained and stored in the storage device 14. Here, the recognition position deviation amount ΔL is obtained by the difference between the measured value La and the true value Lb of the horizontal distance between the two marks 26 and 27 (the distance between the recognition positions of the two marks 26 and 27).
ΔL = La-Lb

  When the two marks 26 and 27 of the recognition position deviation correction jig 25 are imaged by the mark camera 20, the height position of the reference mark 26 is made to coincide with the reference height position. Here, the reference height position coincides with the height positions of the upper surfaces of both sides of the circuit board 22 positioned by the stopper of the clamp device 17.

  In the present invention, the two marks 26 and 27 of the recognition misregistration correction jig 25 may be placed in the field of view of the mark camera 20 at the same time. However, since the field of view of the mark camera 20 is narrow, the two marks 26 and 27 27 may not be simultaneously accommodated in the field of view of the mark camera 20. In addition, if a camera using a telecentric lens is used, the displacement of the recognition position due to parallax and aberration can be eliminated. However, a camera using a telecentric lens is expensive and large, and satisfies the demands for cost reduction and space saving. I can't.

  Therefore, in the present embodiment, even if a telecentric lens is not used, considering that the influence of the parallax and aberration of the lens decreases as the distance from the center of the field of view of the mark camera 20 decreases, When the two marks 26 and 27 are imaged by the mark camera 20, first, as shown in FIG. 4, the reference mark 26 is first imaged by positioning the center of the reference mark 26 near the center of the visual field of the mark camera 20. After recognizing the coordinates (X1, Y1) of the center position [see FIG. 5], the mark camera 20 is moved in the direction from the reference mark 26 to the correction mark 27 by the true value Lb of the horizontal distance between the two marks 26, 27. The correction mark 27 is moved horizontally, and the correction mark 27 is imaged by the mark camera 20 to recognize the coordinates (X2, Y2) of the center position of the correction mark 27 [see FIG. 6].

  In this case, the mark camera 20 is moved in the direction from the reference mark 26 to the correction mark 27 by the true value Lb of the horizontal distance between the two marks 26 and 27 and the correction mark 27 is imaged by the mark camera 20. If the height position of the correction mark 27 is the same as the height position of the reference mark 26, the recognition position (X2, Y2) of the correction mark 27 matches the recognition position (X1, Y1) of the reference mark 26. Actually, since the height difference H is provided between the two marks 26, 27, the recognition position (X2, Y2) of the correction mark 27 is determined according to the height difference H and the inclination of the optical axis of the mark camera 20. ) Deviates from the recognition position (X1, Y1) of the reference mark 26. The shift direction of the recognition position (X2, Y2) of the correction mark 27 with respect to the recognition position (X1, Y1) of the reference mark 26 becomes the shift direction of the recognition position of the correction mark 27 that varies depending on the tilt direction of the optical axis of the mark camera 20. .

  FIG. 7 is an image obtained by combining the captured image of the reference mark 26 shown in FIG. 5 and the captured image of the correction mark 27 shown in FIG. In the image of FIG. 7, the distance between the two marks 26, 27 is the recognition position shift amount ΔL at the height difference H between the two marks 26, 27 (the measured value La of the horizontal distance between the two marks 26, 27 and true The vector direction extending from the recognition position (X1, Y1) of the reference mark 26 to the recognition position (X2, Y2) of the correction mark 27 is the shift direction of the recognition position.

Accordingly, the X-direction deviation amount ΔLX and the Y-direction deviation amount ΔLY of the recognition position of the correction mark 27 are obtained by the following equations.
ΔLX = X2-X1
ΔLY = Y2−Y1
The X / Y direction deviation amounts ΔLX and ΔLY of the recognition position of the correction mark 27 may be stored in the storage device 14 as correction data (recognition position deviation correction amount).

  If the fiducial mark 26 is positioned near the center of the field of view of the mark camera 20 as in this embodiment, the influence of the parallax and aberration of the lens can be reduced without using a telecentric lens. The position can be recognized with high accuracy, and the mark camera 20 can be moved horizontally in the direction from the reference mark 26 toward the correction mark 27 so that the correction mark 27 can be brought close to the center of the field of view of the mark camera 20 and imaged. it can. As a result, the position of the correction mark 27 can also be recognized with less influence of the parallax and aberration of the lens, and the recognized positional deviation amounts ΔLX and ΔLY at the height difference H between the two marks 26 and 27 can be obtained with high accuracy. it can.

  When positioning the recognition position deviation correction jig 25 in advance, if the straight line connecting the centers of the two marks 26 and 27 is parallel to the X axis or the Y axis, the mark camera 20 is used as a reference. The movement of moving horizontally from the mark 26 to the correction mark 27 is movement only in the X or Y direction, and the movement of moving the mark camera 20 horizontally by the true value Lb of the horizontal distance between the two marks 26 and 27 is easy. It becomes.

  As described above, the recognition position deviation amounts ΔLX and ΔLY (correction data) at the height difference H between the two marks 26 and 27 of the recognition position deviation correction jig 25 are obtained and stored in the storage device 14, and then the clamping device 17. In this state, the height position h of the reference position mark 23 on the upper surface of the circuit board 22 is measured by the distance sensor 21 in a state where the upper surfaces of both sides of the circuit board 22 are positioned at the reference height position. At this time, the height position h of the reference position mark 23 from the reference height position is measured.

  Thereafter, as shown in FIG. 8, the mark camera 20 is moved to a position for recognizing the reference position mark 23 on the upper surface of the circuit board 22 to image the reference position mark 23, and the center position of the reference position mark 23 is obtained from the captured image. (X0, Y0) is recognized [see FIG. 9].

Thereafter, the ratio h / H of the height position h of the reference position mark 23 of the circuit board 22 to the height difference H of the two marks 26 and 27 of the recognition position deviation correction jig 25 and the recognition stored in the storage device 14. The coordinates (X0, Y0) of the recognition position of the reference position mark 23 are corrected by the following equation using the X / Y direction displacement amounts ΔLX, ΔLY of the position, and the coordinates of the recognition position of the corrected reference position mark 23 are corrected. Find (X, Y).
X = (X0−ΔLX) × h / H
Y = (Y0−ΔLY) × h / H

  According to the present embodiment described above, the positions of the two marks 26 and 27 of the recognition misalignment correction jig 25 are recognized in advance from the captured image of the mark camera 20 and the height difference H between the two marks 26 and 27 is determined. Only by obtaining the recognition position deviation amounts ΔLX and ΔLY, the recognition position of the reference position mark 23 due to the difference between the inclination of the optical axis of the mark camera 20 from the vertical direction and the height position of the reference position mark 23 of the circuit board 22. It is possible to correct the shift of the recognition position of the reference position mark 23, and it is possible to correct the shift of the recognition position of the reference position mark 23 more easily than in the past.

The present invention is applicable not only to mounting components on the circuit board 22 but also to mounting (stack mounting) small components on the components mounted on the circuit board 22.
Further, the reference position portion provided on the mounting surface on which the component is mounted is not limited to the reference position mark 23, and any one of a specific wiring pattern, a land, a specific shape portion of the mounted component, a terminal, or the like is used as the reference position portion. Even when the mounting position of a component is determined, the present invention can be applied.

  In addition, the present invention is not limited to the shape of the marks 26 and 27 provided on the recognition misalignment correction jig 25, but may be changed to a shape such as “+” or “♦”. Various modifications can be made without departing from the scope.

  DESCRIPTION OF SYMBOLS 11 ... Control apparatus (image processing means), 14 ... Memory | storage device (memory | storage means), 15 ... Adsorption nozzle moving apparatus, 16 ... Board | substrate conveyance apparatus, 17 ... Clamp apparatus, 20 ... Mark camera (camera), 21 ... Distance sensor ( Height position measuring means), 22 ... circuit board, 23 ... reference position mark (reference position portion), 25 ... recognition position deviation correction jig, 26 ... reference mark, 27 ... correction mark

Claims (5)

A camera that captures an image of a reference position provided on a mounting surface for mounting the component from above, and the component that recognizes the position of the reference position from a captured image of the camera and uses the position of the reference position as a reference In a component mounter equipped with image processing means for determining the mounting position of
As a jig for correcting the deviation of the recognition position of the reference position portion due to the difference between the tilt of the optical axis of the camera from the vertical direction and the height position of the reference position portion, two marks are provided on the upper surface side as predetermined jigs. Using a recognition position deviation correction jig formed with a height difference and separated by a predetermined horizontal distance,
The image processing means captures in advance two marks of the recognition position deviation correction jig with the camera, recognizes the positions of the two marks from the captured image, and determines the recognition position in the height difference of the two marks. When data relating to the amount of deviation (hereinafter referred to as “correction data”) is stored in a storage unit, and a reference position provided on the mounting surface is imaged by the camera to recognize the position of the reference position In addition, the height difference between the height position of the reference position portion and the reference height position, the height difference between the two marks of the recognition position deviation correction jig, and the correction data stored in the storage means are used. A component mounting machine that corrects a deviation in a recognition position of the reference position portion due to a difference in inclination of the optical axis of the camera from a vertical direction and a height position of the reference position portion.   The two mark of the recognition position deviation correction jig is imaged by the camera, and the height position of one of the two marks is matched with the reference height position. The component mounting machine according to 1.   When the image processing means captures the two marks of the recognition misregistration correction jig with the camera, the image processing means positions the one mark near the center of the field of view of the camera to capture the position of the one mark. Then, the camera is moved horizontally in the direction of the other mark by the true value of the horizontal distance between the two marks, and the other mark is imaged by the camera to recognize the position of the other mark. The component mounter according to claim 1, wherein the component mounter is used. The mounting surface for mounting the component is the upper surface of the circuit board,
A clamp device is provided for positioning the upper surfaces of both sides of the circuit board at the reference height position by abutting and clamping both sides of the circuit board from below to a stopper for determining the reference height position. The component mounting machine according to any one of claims 1 to 3. The reference position portion provided on the mounting surface on which the component is mounted is picked up by the camera from above, the position of the reference position portion is recognized from the captured image of the camera, and the component is based on the position of the reference position portion. In the image processing method for determining the mounting position of
As a jig for correcting the deviation of the recognition position of the reference position portion due to the difference between the tilt of the optical axis of the camera from the vertical direction and the height position of the reference position portion, two marks are provided on the upper surface side as predetermined jigs. Using a recognition position deviation correction jig formed with a height difference and separated by a predetermined horizontal distance,
Data relating to the amount of deviation of the recognition position in the height difference between the two marks by recognizing the positions of the two marks from the picked-up image by imaging two marks of the recognition position deviation correction jig in advance. (Hereinafter referred to as “correction data”) is stored in the storage means, and when the reference position portion provided on the mounting surface is imaged by the camera and the position of the reference position portion is recognized, the reference position portion Using the height difference between the height position and the reference height position, the height difference between the two marks of the recognition position deviation correction jig, and the correction data stored in the storage means. An image processing method, comprising: correcting a deviation of a recognition position of the reference position portion due to a difference between an inclination of the shaft from a vertical direction and a height position of the reference position portion.

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