Component mounting device

Abstract

This component mounting device 100 comprises a head that is provided to be capable of moving in the horizontal and vertical directions relative to a substrate P on which a component E is to be mounted and is for mounting the component E at a mounting position on the substrate P, a monocular oblique camera 8 that is fixed to the head and can capture images from a direction that is inclined exactly an angle θ (0°<θ<90°) of incline relative to a horizontal plane, and a control unit that acquires height information for the substrate P at the mounting position on the basis of oblique images captured by the oblique camera 8 and corrects a target lowering position for the head on the basis of the acquired height information. The oblique images include a pre-mounting image that captures the substrate P before component mounting and a post-mounting image that captures the substrate P after component mounting, and the control unit acquires a difference image for the pre-mounting image and the post-mounting image and calculates the height information using the displacement amount between the position of the component E in the acquired difference image and a reference position.

Description

Component Mounting Equipment

[0001] The present disclosure relates to a component mounting apparatus.

[0002] In recent years, surface mounters have been required to improve reliability by miniaturizing components, and an imaging device capable of capturing images of the suction and mounting point may be disposed on the head or the like. For example, the surface mounter described in Japanese Patent Laid-Open No. 2008-103426 (Patent Document 1 below) is equipped with an imaging device disposed on the suction mounting head. The suction mounting head has a head body, a suction nozzle, and a bracket. The imaging device is connected to the head body via the bracket. The imaging device is a so-called oblique camera, and is disposed obliquely to avoid the suction nozzle that picks up and mounts the components.

[0003] Furthermore, in order to reduce the stress and impact on components due to miniaturization of components, attempts have been made to measure the warpage and height of the board and correct the target lowering position. As an attempt to correct the target lowering position while being equipped with the above-mentioned oblique camera, for example, a component mounting device described in Japanese Patent No. 6534447 (Patent Document 2 below) is known.

[0004] JP 2008-103426 A Japanese Patent No. 6534447 A

[0005] The component mounting device of Patent Document 2 can capture images and measure heights quickly and without tactile loss, but requires a stereo camera to be mounted on the head, which poses issues such as the complexity, weight, and cost of the device.

[0006] The component mounting device of the present disclosure includes a head that is movable horizontally and vertically relative to a board on which a component is to be mounted, and that mounts the component at a mounting position on the board; a monocular oblique camera that is fixed to the head and is capable of capturing images from a direction inclined by an inclination angle θ (0°<θ<90°) with respect to the horizontal plane; and a control unit that acquires height information of the board at the mounting position based on oblique images captured by the oblique camera, and corrects a target lowering position of the head based on the acquired height information, wherein the oblique images include a pre-mounting image captured of the board before components are mounted, and a post-mounting image captured of the board after components have been mounted, and the control unit acquires a differential image between the pre-mounting image and the post-mounting image, and calculates the height information using the amount of displacement between the position of the component in the acquired differential image and a reference position.

[0007] According to the present disclosure, height information of a substrate can be calculated using only an inexpensive and simple monocular oblique camera.

[0008] FIG. 1 is a diagram illustrating the overall configuration of a component mounting apparatus according to a first embodiment. FIG. 2 is a block diagram illustrating the control configuration of the component mounting apparatus according to the first embodiment. FIG. 3 is a diagram illustrating the imaging of a mounting position using an oblique camera according to the first embodiment. FIG. 4 is a diagram illustrating the operation of a mounting head of the component mounting apparatus according to the first embodiment. FIG. 5A is a diagram illustrating an imaging point of the component mounting apparatus according to the first embodiment, FIG. 5B is a pre-mounting image, and FIG. 5C is a post-mounting image. FIG. 6 is a diagram illustrating a difference image. FIG. 7 is a perspective view illustrating the center position of a component underside. FIG. 8A is a side view illustrating the imaging of a component using an oblique camera, and FIG. 8B is an oblique image of the component captured by the oblique camera. FIG. 9 is a diagram illustrating the calculation of height information. FIG. 10A is a diagram illustrating the displacement ΔY between the position of a component in the difference image and a reference position, and FIG. 10B is a diagram illustrating the calculation of height information. FIG. 11 is a diagram illustrating the imaging of a mark on a mounting jig using an oblique camera. FIG. 12 is a diagram showing an image of a hole in a suction jig captured by an oblique camera. FIG. 13 is a diagram showing a process of correcting a target lowering position based on a height map. FIG. 14A is a diagram showing multiple components held on a component tape according to the first embodiment, FIG. 14B is a pre-suction image, and FIG. 14C is a post-suction image. FIG. 15 is a flowchart illustrating the suction operation. FIG. 16 is a flowchart illustrating the mounting operation. FIG. 17 is a diagram illustrating the matching process according to the second embodiment. FIG. 18 is a flowchart illustrating a noise removal method. FIG. 19 is a diagram illustrating the presence or absence of suction misalignment according to the third embodiment. FIG. 20 is a diagram illustrating the difference between oblique images depending on whether or not there is a suction misalignment. FIG. 21 is a diagram illustrating the difference between differential images depending on whether or not there is a suction misalignment.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] [1] A component mounting device according to the present disclosure includes a head that is movable horizontally and vertically relative to a board on which a component is to be mounted and that mounts the component at a mounting position on the board; a monocular oblique camera that is fixed to the head and is capable of capturing images from a direction inclined by an inclination angle θ (0°<θ<90°) with respect to a horizontal plane; and a control unit that acquires height information of the board at the mounting position based on oblique images captured by the oblique camera and corrects a target lowering position of the head based on the acquired height information, wherein the oblique images include a pre-mounting image captured of the board before component mounting and a post-mounting image captured of the board after component mounting, and the control unit acquires a difference image between the pre-mounting image and the post-mounting image and calculates the height information using the amount of displacement between the position of the component in the acquired difference image and a reference position.

[0011] According to this configuration, height information is calculated based on a differential image between a pre-mounting image taken with a monocular oblique camera before component mounting and a post-mounting image taken with the same monocular oblique camera after component mounting, so that board height information can be calculated using only an inexpensive and simple monocular oblique camera.

[0012] [2] The component mounting device of the present disclosure comprises: a head that is movable horizontally and vertically relative to a component tape on which components are stored, and that picks up the components at a pick-up position on the component tape; a monocular oblique camera that is fixed to the head and that can capture images from a direction inclined by an inclination angle θ (0°<θ<90°) with respect to the horizontal plane; and a control unit that acquires height information for the pick-up position based on the oblique images captured by the oblique camera and corrects a target lowering position of the head based on the acquired height information, wherein the oblique images include a pre-pickup image captured of the component tape before the components are picked up, and a post-pickup image captured of the component tape after the components have been picked up, and the control unit acquires a difference image between the pre-pickup image and the post-pickup image, and calculates the height information using the amount of displacement between the position of the component in the acquired difference image and a reference position.

[0013] According to this configuration, height information is calculated based on a differential image between a pre-suction image taken by a monocular oblique camera before component suction and a post-suction image taken by the same oblique camera after component suction, so that board height information can be calculated using only an inexpensive and simple monocular oblique camera.

[0014] [3] In the above [1] or [2], it is preferable that the control unit calculates a difference in pixel count (pix), which is the amount of offset between the position of the component in the difference image and the reference position, and calculates a height variation (μm) as the height information using the following formula: Calculation formula: Height variation (μm) = (difference in pixel count (pix) * resolution (μm / pix)) / cos (tilt angle θ) With this configuration, the height variation (μm) can be calculated from the difference in pixel count in the difference image.

[0015] [4] In any one of [1] to [3] above, it is preferable that the reference position is the position of the reference point on an oblique image of the reference point captured by the oblique camera when a jig having the reference point is at a reference height.

[0016] With this configuration, if the reference point is located at the position of the component when it is picked up or placed, the position of the reference point in the oblique image becomes the reference height. Height information can be calculated by measuring the amount of movement from the position of the reference point to the position of the component based on the difference image showing the component and the oblique image showing the reference point.

[0017] [5] In any one of [1] to [4] above, if there is a part in the difference image where the area of ​​the part exceeds an area threshold, or if there is a part where the position of the part exceeds a distance threshold, it is preferable that the control unit determines the exceeding part to be noise and removes the exceeding part from the difference image.

[0018] With this configuration, it is possible to calculate highly robust height information by removing noise from the difference image.

[0019] [6] In the above [1], it is preferable that the control unit calculates the amount of positional deviation of the after-attachment image based on the before-attachment image, and obtains the difference image using the before-attachment image and the after-attachment image after correcting the amount of positional deviation.

[0020] With this configuration, a highly accurate differential image can be obtained.

[0021] [7] In the above [2], it is preferable that the control unit calculates the amount of positional shift of the post-adsorption image based on the pre-adsorption image, and obtains the difference image using the pre-adsorption image and the post-adsorption image after correcting the amount of positional shift.

[0022] With this configuration, a highly accurate differential image can be obtained.

[0023] [8] In any of the above [1] to [7], it is preferable that a component recognition camera is provided which captures an image of the component adsorbed to the head and recognizes it, and the control unit calculates the amount of deviation due to adsorption deviation of the component based on the image captured by the component recognition camera, and obtains the difference image using the pre-mounting image and the post-mounting image after correcting the amount of deviation.

[0024] According to this configuration, the amount of deviation due to the adsorption deviation is used to correct the error due to the adsorption deviation, and it is possible to perform measurement with higher accuracy.

[0025] [Details of the Embodiments of the Present Disclosure] The following describes embodiments of the present disclosure. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, for multiple identical components, only some of the components may be designated by reference numerals, and the reference numerals for other components may be omitted.

[0026] 1 to 15, the configuration of a component mounting apparatus 100 according to a first embodiment of the present disclosure will be described. Note that, although the case of mounting is mainly illustrated below, the same applies to the case of suction, so in the case of suction, "mounting" will be read as "suction."

[0027] As shown in FIG. 1, the component mounting apparatus 100 is an apparatus for mounting electronic components such as ICs, transistors, capacitors, and resistors (hereinafter referred to as "components E") onto a substrate P such as a printed circuit board.

[0028] The component mounting apparatus 100 also includes a base 1, a transport unit 2, a head unit 3, a support unit 4, a rail unit 5, a component recognition camera 6, a board recognition camera 7, a monocular oblique camera 8, and a control device 9 (see FIG. 2). The control device 9 is an example of the "control unit" in the claims.

[0029] At both ends of the base 1 in the Y direction (Y1 side and Y2 side), feeder placement sections 12 for placing a plurality of tape feeders 11 are provided.

[0030] The tape feeder 11 holds a reel (not shown) on which a component tape 13 (see FIG. 14A) is wound, which holds a plurality of components E spaced at predetermined intervals. The tape feeder 11 is configured to supply components E from the leading end of the tape feeder 11 by rotating the reel to feed out the component tape 13 holding the components E.

[0031] Each tape feeder 11 is arranged in the feeder arrangement section 12 and electrically connected to the control device 9 via a connector (not shown) provided in the feeder arrangement section 12. As a result, each tape feeder 11 is configured to feed component tape 13 from its reel and supply components E based on a control signal from the control device 9. In this case, each tape feeder 11 is configured to supply components E in accordance with the mounting operation of the head unit 3.

[0032] The transport unit 2 has a pair of conveyors 2a. The transport unit 2 has the function of transporting the substrate P in the horizontal direction (X direction) using the pair of conveyors 2a. Specifically, the transport unit 2 has the function of carrying in the substrate P before mounting from a transport path not shown on the upstream side (X1 side), transporting the carried-in substrate P to a mounting work position M, and carrying out the substrate P after mounting has been completed to a transport path not shown on the downstream side (X2 side). The transport unit 2 is also configured to hold and fix the substrate P stopped at the mounting work position M using a substrate fixing mechanism such as a clamp mechanism.

[0033] The pair of conveyors 2a of the transport section 2 are configured to be able to transport the substrate P in the horizontal direction (X direction) while supporting the substrate P from below. The pair of conveyors 2a are also configured to be able to adjust the distance between them in the Y direction. This makes it possible to adjust the distance between the pair of conveyors 2a in the Y direction according to the size of the substrate P being transported.

[0034] The head unit 3 is configured to mount components E at mounting positions Pa (see FIG. 3) on a substrate P fixed at a mounting work position M. The head unit 3 includes a ball nut 31, five mounting heads 32, five Z-axis motors 33 (see FIG. 2) provided on the five mounting heads 32, respectively, and five R-axis motors 34 (see FIG. 2) provided on the five mounting heads 32, respectively.

[0035] The five mounting heads 32 are arranged in a row along the X direction on the underside of the head unit 3. A nozzle 32a (see FIG. 3) is attached to the tip of each of the five mounting heads 32. The mounting heads 32 are configured to be able to suck and hold the components E supplied from the tape feeder 11 by using negative pressure generated at the tip of the nozzle 32a by a negative pressure generator (not shown).

[0036] The mounting heads 32 are also configured to be able to move up and down in the vertical direction (Z direction). Specifically, the mounting heads 32 are configured to be able to move up and down between a lowered position when performing tasks such as suction and attachment (mounting) of the components E, and an elevated position when transporting and photographing the components E. In the head unit 3, the five mounting heads 32 are configured to be able to move up and down individually by a Z-axis motor 33 provided for each mounting head 32. The five mounting heads 32 are also configured to be able to rotate for each mounting head 32 around the central axis of the nozzle 32 a (around an axis extending in the Z direction) by an R-axis motor 34 provided for each mounting head 32.

[0037] The head unit 3 is also configured to be movable in the X direction along the support portion 4. Specifically, the support portion 4 includes a ball screw shaft 41, an X-axis motor 42 that rotates the ball screw shaft 41, and a guide rail (not shown) that extends in the X direction. When the X-axis motor 42 rotates the ball screw shaft 41, the head unit 3 is configured to be movable in the X direction along the support portion 4 together with the ball nut 31 with which the ball screw shaft 41 is engaged (screwed).

[0038] The support unit 4 is configured to be movable in the Y direction perpendicular to the X direction along a pair of rail units 5 fixed on the base 1. Specifically, the rail units 5 include a pair of guide rails 51 that support both X-direction ends of the support unit 4 so as to be movable in the Y direction, a ball screw shaft 52 extending in the Y direction, and a Y-axis motor 53 that rotates the ball screw shaft 52. The support unit 4 is also provided with a ball nut 43 with which the ball screw shaft 52 is engaged (screwed). When the ball screw shaft 52 is rotated by the Y-axis motor 53, the support unit 4 is configured to be movable in the Y direction along the pair of rail units 5 together with the ball nut 43 with which the ball screw shaft 52 is engaged (screwed).

[0039] With this configuration, the head unit 3 is configured to be movable in horizontal directions (X and Y directions) on the base 1. This allows the head unit 3 to move, for example, above the tape feeder 11 and pick up components E supplied from the tape feeder 11. The head unit 3 can also move, for example, above a substrate P fixed at a mounting work position M and mount the picked-up components E on the substrate P.

[0040] The component recognition camera 6 is configured to capture an image of the component E picked up by the mounting head 32 in order to recognize the suction state of the component E prior to mounting the component E. The component recognition camera 6 is fixed on the upper surface of the base 1, and configured to capture an image of the component E picked up by the mounting head 32 from below (in the Z2 direction) the component E. The image capture results are acquired by the control device 9. This allows the control device 9 to recognize the suction state of the component E (rotational posture, suction position relative to the mounting head 32), the amount of deviation due to suction deviation, etc. based on the image capture results of the picked-up component E.

[0041] The board recognition camera 7 is configured to capture an image of a position recognition mark (fiducial mark) FM that is attached to the board P prior to the mounting of the components E. The position recognition mark FM is a mark for recognizing the position of the board P. In the board P shown in FIG. 1 , a pair of position recognition marks FM are attached at the bottom right and top left positions of the board P. The image capture results of these position recognition marks FM are acquired by the control device 9. Then, based on the image capture results of the position recognition marks FM, the control device 9 can recognize the exact position and orientation of the board P that is fixed by a board fixing mechanism (not shown).

[0042] The board recognition camera 7 is attached to the X2 side of the head unit 3, and is configured to be movable in the X and Y directions on the base 1 together with the head unit 3. The board recognition camera 7 is configured to move horizontally (X and Y directions) on the base 1 and capture an image of the position recognition mark FM attached to the board P from above the board P (Z1 direction).

[0043] The oblique camera 8 is a monocular oblique camera 8, and as shown in Fig. 3, is configured to be able to capture an image of the substrate P. Specifically, the oblique camera 8 is configured to be able to capture an image of the vicinity of the mounting position Pa of the substrate P in order to measure the height of the vicinity of the mounting position Pa.

[0044] The oblique camera 8 is configured to be able to capture, from an oblique direction, an image of a predetermined area near the mounting position Pa of the substrate P. Specifically, the oblique camera 8 is configured to be able to capture an image of the predetermined area near the mounting position Pa of the substrate P from an imaging direction inclined by an inclination angle θ (0°<θ<90°) with respect to the horizontal plane (a plane approximately parallel to the substrate surface Pb on which the component E is mounted).

[0045] As a result, the oblique camera 8 is configured to be able to image a predetermined area near the mounting position Pa from an imaging direction inclined with respect to the board surface Pb of the board P. The imaging results of the predetermined area near the mounting position Pa are acquired by the control device 9. Then, based on the imaging results of the predetermined area near the mounting position Pa, the control device 9 acquires height information about the area near the mounting position Pa.

[0046] 2, the control device 9 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and is configured to control the operation of the component mounting apparatus 100. Specifically, the control device 9 is configured to mount components E on the board P by controlling the transport unit 2, the X-axis motor 42, the Y-axis motor 53, the Z-axis motor 33, the R-axis motor 34, etc. in accordance with a pre-stored program.

[0047] Specifically, the control device 9 is configured to move the head unit 3 above the tape feeder 11 and generate negative pressure in the nozzle 32a of the mounting head 32 using a negative pressure generator (not shown), so that the component E supplied from the tape feeder 11 is adsorbed onto the nozzle 32a.

[0048] The control device 9 is configured to move the head unit 3 from above the tape feeder 11 to above the substrate P in order to mount the picked-up components E on the substrate P. During this movement, the control device 9 is configured to move the head unit 3 so that it passes above the component recognition camera 6, and to cause the component recognition camera 6 to capture an image of the components E picked up by each mounting head 32.

[0049] 4, the control device 9 is configured to start the lowering operation of the mounting head 32 before the mounting head 32 reaches a position directly above the mounting position Pa. This allows the lowering operation (movement in the height direction) of the mounting head 32 to be performed in parallel with movement in the horizontal direction (XY directions), thereby making it possible to shorten the time required to mount the component E.

[0050] The control device 9 is configured to stop the supply of negative pressure to the mounting head 32 at a predetermined timing, thereby mounting (attaching) the picked-up component E onto the substrate P. At this time, the control device 9 is configured to mount the component E onto the substrate P in a state in which the target lowered position of the mounting head 32 has been corrected.

[0051] The control device 9 is configured to perform three operations while the mounting head 32 is moving: capturing an image of a predetermined area near the mounting position Pa using the oblique camera 8, obtaining height information of the board surface Pb of the board P near the mounting position Pa based on the image capturing results from the oblique camera 8, and correcting the target lowering position of the mounting head 32 based on the obtained height information. This makes it possible to mount the component E on the board P with an appropriate push-in amount.

[0052] Specifically, the control device 9 is configured to correct the target lowering position of the mounting head 32 upward in the height direction when it is determined that the substrate P is misaligned upward (in the Z1 direction) with respect to the reference plane based on the acquired height information of the substrate surface Pb of the substrate P near the mounting position Pa. Furthermore, the control device 9 is configured to correct the target lowering position of the mounting head 32 downward in the height direction when it is determined that the substrate P is misaligned downward (in the Z2 direction) with respect to the reference plane based on the acquired height information of the substrate surface Pb of the substrate P near the mounting position Pa.

[0053] (Configuration of control device related to acquisition of height information) In this embodiment, a method for calculating height information of the substrate surface Pb using only the monocular oblique camera 8 is disclosed. This eliminates the need for a stereo optical system or a displacement sensor, thereby achieving a significant simplification of the configuration and cost reduction. As a method, images taken by the oblique camera 8 during normal operation while the device is normally worn are used.

[0054] Fig. 5(A) shows the state in which the oblique camera 8 captures images before and after mounting at the mounting position Pa while the mounting head 32 moves from the right side to the left side in the figure. Fig. 5(B) is an oblique image captured by the oblique camera 8 before mounting (pre-mounting image), and Fig. 5(C) is an oblique image captured by the oblique camera 8 after mounting (post-mounting image). In this embodiment, the pre-mounting image and the post-mounting image are captured at the same height position of the mounting head 32.

[0055] Because the mounting head 32 moves in the X direction, the imaging point of the before-mounting image and the imaging point of the after-mounting image are shifted by ΔX1. That is, the mounting position Pa in the before-mounting image appears to the left of the mounting position Pa in the after-mounting image by ΔX1. For this reason, if the before-mounting image and the after-mounting image are directly matched without taking ΔX1 into consideration, the difference between the images will be large.

[0056] Therefore, the amount of positional deviation of the after-attachment image based on the before-attachment image is calculated, and the after-attachment image is corrected using this amount of positional deviation to obtain the corrected after-attachment image, and the matching process is performed by matching this corrected after-attachment image to the before-attachment image. For example, the after-attachment image can be corrected by a method such as shifting the after-attachment image little by little in the X and Y directions and using the amount of positional deviation that minimizes the difference between the before-attachment image and the corrected after-attachment image.

[0057] 6A shows a difference image DI obtained by matching a pre-mounting image and a corrected post-mounting image so as to minimize the inter-image difference. When the brightness of each pixel in each image is quantified, for example, in 256 gradations, the pixel values ​​are quantified from 0 to 255. When corresponding pixels in the pre-mounting image and the corrected post-mounting image are subtracted, if the result is 0, the result is black. Therefore, the black color around component E indicates that the result of the subtraction was 0. The inter-pixel difference described above may be calculated by aggregating the absolute values ​​of the values ​​obtained by subtraction for all pixels.

[0058] 6B indicates the position of component E in the differential image DI. The center position of component E in the differential image DI may be used as the detected position, with some error included. However, since component E in this embodiment is a rectangular parallelepiped component whose outer dimensions are known, it is appropriate to use the center position of the bottom surface of component E, which serves as the reference for the height of the board surface Pb, as the position of component E. However, the position of component E cannot be directly recognized by the oblique camera 8.

[0059] The x marks in Figures 7 and 8 indicate the position Ea of the component E. Figures 7 and 8 simplify the shape of the component E, showing the bottom surface E1, a long side surface E2 rising from the long side of the bottom surface E1, a short side surface E3 rising from the short side of the bottom surface E1, and a top surface E4. The position Ea of the component E is the center position of the bottom surface E1. Figure 8(A) is a side view of the position Ea of the component E as seen from the short side surface E3 side. The tilt angle of the oblique camera 8 with respect to the board surface Pb (horizontal plane) is θ (0°<θ<90°).

[0060] 8B is a perspective view of position Ea of component E as viewed from the imaging direction ID of oblique camera 8. In FIG. 8B, the bottom surface E1 of component E is hidden by the top surface E4 and the long side surface E2, so that position Ea of component E cannot be imaged by oblique camera 8 and cannot be directly recognized.

[0061] Therefore, the control device 9 calculates the position Ea1 of the component E in the differential image DI as shown in FIG. 9 . As described above, the position Ea of the component E cannot be directly recognized, so the position Ea1 of the component E is calculated using the position Eb of the long side of the bottom surface of the component E. The position corresponding to Eb in the differential image DI (the bottom end in the differential image DI) is defined as Eb1. Since the size of the component E is known, if the distance between Ea and Eb (half the distance of the short side of the component E) is defined as L, the distance between Ea1 and Eb1 is L / sin θ. Therefore, if the upper left corner of the differential image DI is the origin (x, y) = (0, 0) and the downward direction of the Y axis is defined as the positive direction, the position Ea1 of the component E in the differential image DI can be calculated as Eb1 - L / sin θ.

[0062] Similarly, the control device 9 calculates the reference position Ec1 in the differential image DI as shown in FIG. 9 . The component E indicated by the two-dot chain line in FIG. 9 represents the component E when the warpage of the substrate P is zero and the height is zero. The position of the center of the lower surface of the component E is defined as Ec. The position of the component E reflected in the differential image DI shown in FIG. 10A is defined as the reference position Ec1. The distance between the position Ea1 of the component E in the differential image DI and the reference position Ec1 is defined as the displacement ΔY (μm). The displacement ΔY can be calculated by multiplying the number of pixels by the resolution (μm / pix). Therefore, as shown in FIG. 10B, the height information (μm) of the substrate P can be calculated using the following formula: Height information (μm) = (number of pixels by the difference (pix) * resolution (μm / pix)) / cos θ (Method of obtaining the reference position) The reference position Ec1 for component mounting is obtained using a mounting jig 60 shown in FIG. 11 . The mounting jig 60 is configured by fitting a glass substrate 62 into a metal frame 61, and a + mark 63 is provided at the center of the glass substrate 62 as a reference position. The mounting jig 60 is transported to the mounting work position M, and an image of the mark 63 is taken by the oblique camera 8 with an XY trace being drawn on the center of the mark 63.

[0063] Normally, the center position of the oblique image captured by the oblique camera 8 coincides with the position of the mounting head 32. Therefore, the center position of the oblique image capturing the mark 63 is the position of the mounting head 32. However, to use the mark 63 as a reference point, it is necessary to correct the center position of the oblique image so that it coincides with the mounting position Pa of the component E. To perform such correction, the mark 63 is captured by the oblique camera 8 with an XY trace applied.

[0064] Thereafter, the position of the mark 63 as the reference position in the differential image DI is memorized by prior teaching. In this way, the height information can be calculated by measuring the amount of displacement from the position of the mark 63 to the position Ec1 of the component E based on the differential image DI in which the component E is captured and the oblique image in which the mark 63 is captured.

[0065] Similarly, the reference position for component suction is obtained using a suction jig 70 shown in Fig. 12. The suction jig 70 has a circular hole 71 disposed as a reference position on the suction surface (horizontal plane) of the tape feeder 11. An XY trace is drawn to the center of the circular hole 71, and the image of the circular hole 71 is captured by the oblique camera 8. Thereafter, the location of the circular hole 71 as the reference position in the differential image DI is memorized by prior teaching.

[0066] (Creating and Updating Height Map) Once a certain amount of height information for the board P calculated using the difference image DI has been accumulated, a height map can be created based on this height information, and the target lowering position can be corrected based on the height map at the time of the next mounting. The squares, triangles, and stars in Figure 13 indicate the positions and heights of components E that have already been acquired, and the circles indicate the positions and heights of components E to be mounted next. The board surface Pb of the board P can be approximately calculated from the height information such as the squares, triangles, and stars, and the height of the circle that is the next mounting point can be predicted. When new height information is obtained, the height map is updated.

[0067] (Method for calculating pickup surface height information during component pickup) The method for calculating height information of the board P when mounting components E has been described above, but the above method can also be used to calculate pickup surface height information when components E are picked up from the component tape 13. Fig. 14A shows multiple components E arranged on the component tape 13. Fig. 14B shows a pre-pickup image, which is an oblique image before the components E are picked up, and Fig. 14C shows a post-pickup image, which is an oblique image after the components E have been picked up. The control device 9 obtains a difference image DI by performing a matching process while aligning the post-pickup image with the pre-pickup image, and calculates pickup surface height information based on the amount of displacement between the position of the component E in the difference image DI and the reference position.

[0068] (Explanation of Pickup Operation) Next, the pickup operation will be described with reference to the flowchart in Fig. 15. A pre-pickup image is captured by the oblique camera 8 (step S10), and after component E is picked up, a post-pickup image is captured (step S11). In the case of the first pickup point (Yes in step S12), a matching process is performed (step S13), and a difference image DI is obtained (step S14).

[0069] Blob extraction is performed on the difference image, and the location of a block with a certain or greater difference in brightness between the front and rear is calculated (step S15), and the center position of the component E extracted as the block is calculated (step S16). After this, the component E is imaged by the component recognition camera 6, and the amount of pickup deviation of the component E is calculated based on the image (step S17). Furthermore, height information of the pickup point is calculated based on the difference image DI (step S18).

[0070] When pickup of all components E is complete (Yes in step S19), the pickup operation ends, and if pickup is not complete (No in step S19), the process returns to step S10 and a pre-pickup image is captured.

[0071] (Description of Mounting Operation) Next, the mounting operation will be described with reference to the flowchart in FIG. 16 . In the case of the first mounting point (Yes in step S20), the first-point operation mode is executed (step S21). The first-point operation mode is, for example, to slowly lower the mounting head 32 that has picked up the component E toward the mounting position Pa. This prevents the component E or the mounting head 32 from colliding with the substrate P. From the second point onward (No in step S20), it is possible to predict, based on the height information of the substrate P obtained at the first point, how high the mounting head 32 can be lowered without colliding with the substrate P, and therefore the mounting head 32 can be operated at a higher speed than at the first point.

[0072] A pre-mounting image is captured by the oblique camera 8 (step S22), and after component E is mounted at mounting position Pa, a post-mounting image is captured (step S23). A matching process is performed on the post-mounting image using the pre-mounting image as a reference (step S24), and a difference image DI is obtained (step S25). Blob extraction is performed on the difference image, and the location of a block with a front-to-back luminance difference of a certain level or more is calculated (step S26), and the center position of component E extracted as a block is calculated (step S27).

[0073] Height information for the mounting points is calculated using the amount of displacement between the position of component E in the differential image DI and the reference position (step S28), and the height map is updated (step S29). The target lowering position is corrected based on the calculated height information. When mounting of all components E is complete (Yes in step S30), the mounting operation ends. If mounting is not complete (No in step S30), the process returns to steps S20 and S22, and pre-mounting images are captured again. Note that for the second and subsequent points, the target lowering positions may be corrected by referring to the height map.

[0074] 17 and 18 , a second embodiment of the present disclosure will be described. An actual difference image may not be the ideal difference image described in the first embodiment, and noise may occur. In this case, a check may be performed based on component size information to determine whether the difference is a component or noise.

[0075] 17A shows an image of component E before it is mounted (before it is mounted), and FIG. 17B shows an image of component E after it is mounted (after it is mounted). At the left edge of the after-mounting image, part of the adjacent mounting position Pa is reflected as noise N1. In such a case, even if the difference image shown in FIG. 17C is acquired after taking into account the positional shift in the after-mounting image, it is conceivable that noise N2 will still remain.

[0076] Here, whether or not noise N2 is noise may be determined by determining that the area of ​​part E exceeds an area threshold or the position of part E exceeds a distance threshold in the difference image. In such cases, the exceeding portion may be removed from the difference image.

[0077] A specific noise removal method will be described with reference to the flowchart in Fig. 18. When a difference image is acquired (step S40), chunks are extracted and their areas are checked (step S41). If there are any chunks whose area exceeds the area threshold (No in step S42), they are determined to be noise and removed (step S43). On the other hand, if the area of ​​the chunk does not exceed the area threshold (Yes in step S42) or if all chunks have not been checked (No in step S44), the process returns to step S41 and the areas of other chunks are checked.

[0078] Once the area check is complete for all the masses, a position check is performed (step S45). The position check is performed by determining whether or not a mass is located in an appropriate position. For example, the determination may be made by determining whether or not the distance from the largest mass exceeds a distance threshold. If it is determined that no mass is located in an appropriate position (No in step S46), an abnormality is notified (step S47). If it is determined that a mass is located in an appropriate position (Yes in step S46), height information calculation processing is performed (step S48).

[0079] 19 to 21 , a third embodiment of the present disclosure will be described. If the substrate P is not warped and the component E is picked up at the ideal center position, the component E will be positioned at the center of the post-mounting image. However, if the component E is picked up at a position offset relative to the nozzle 32a, the component E will be misaligned in both the pre-mounting image and the post-mounting image by the amount of the suction offset, and the component E will appear misaligned in both images. Simply looking at the images makes it impossible to determine whether the component E is misaligned due to a change in the height of the substrate P or due to suction offset. The amount of offset due to suction offset is measured by the component recognition camera 6 between the time the component E is picked up by the nozzle 32a and the time it is placed on the substrate P. Therefore, the measured amount of offset can be used to correct for any positional error in the component E.

[0080] Fig. 19(A) shows component E being picked up in the ideal center position, and Fig. 19(B) shows component E being picked up offset from nozzle 32a. Fig. 20(A) is a post-mounting image without any suction offset, and Fig. 20(B) is a post-mounting image with a suction offset. The slight shift in the image in Fig. 20(B) to the lower right compared to the image in Fig. 20(A) is due to the suction offset. Similarly, the slight shift in the difference image in Fig. 21(B) to the lower right compared to the difference image in Fig. 21(A) is due to the suction offset.

[0081] Since calculating height information using the difference image of Fig. 21(B) will result in errors in the height information, errors in the height information can be reduced by calculating the height information in a state where the factors that cause suction displacement are eliminated, as in the difference image of Fig. 21(A), or by correcting the suction displacement after calculating the height information using the difference image of Fig. 21(B). According to this embodiment, highly robust height information can be calculated by removing noise from the difference image.

[0082] Other Embodiments (1) In the above embodiment, the mounting position Pa of the component E is imaged by the oblique camera 8 while the mounting head 32 is moving. However, the image may be captured while the mounting head 32 is stationary. In this case, the post-mounting image and the post-suction image can be used as they are without correcting the amount of misalignment.

[0083] (2) In the above embodiment, chunks extracted by blob extraction are recognized as parts, but whether or not a part is a part may be determined using AI.

[0084] (3) In the above embodiment, the position Ea of the component E is the center of the bottom surface of the component E. However, in the case of a lead component, for example, the position of the lead tip may be the component position.

[0085] 1: Base 2: Transport section 2a: Conveyor 3: Head unit 4: Support section 5: Rail section 6: Component recognition camera 7: Board recognition camera 8: Oblique camera 9: Control device (control section) 11: Tape feeder 12: Feeder placement section 13: Component tape 31: Ball nut 32: Mounting head 32a: Nozzle 33: Z-axis motor 34: R-axis motor 41: Ball screw shaft 42: X-axis motor 43: Ball nut 51: Guide rail 52: Ball screw shaft 53: Y-axis motor 60: Mounting jig 61: Frame 62: Glass substrate 63: Mark (reference point) 70: Suction jig 71: Round hole (reference point) 100: Component mounting device DI: Difference image E: Component Ea, Ea1: Position Eb, Eb1: Position Ec, Ec1: Position E1: Bottom surface E2: Long side E3: Short side E4: Top surface ID: Imaging direction M: Mounting work position N1: Noise N2: Noise P: Board Pa: Mounting position Pb: Board surface

Claims

1. A component mounting device comprising: a head that is movable horizontally and vertically relative to a board on which components are to be mounted, and that mounts the components at a mounting position on the board; a monocular oblique camera that is fixed to the head and can capture images from a direction inclined by an inclination angle θ (0°<θ<90°) with respect to the horizontal plane; and a control unit that acquires height information of the board at the mounting position based on oblique images captured by the oblique camera, and corrects a target lowering position of the head based on the acquired height information, wherein the oblique images include a pre-mounting image captured of the board before components are mounted, and a post-mounting image captured of the board after components have been mounted, and the control unit acquires a differential image between the pre-mounting image and the post-mounting image, and calculates the height information using the amount of displacement between the position of the component in the acquired differential image and a reference position.

2. A component mounting device comprising: a head that is movable horizontally and vertically relative to a component tape containing components and that picks up the components at a pick-up position on the component tape; a monocular oblique camera that is fixed to the head and can capture images from a direction inclined by an inclination angle θ (0°<θ<90°) with respect to the horizontal plane; and a control unit that obtains height information for the pick-up position based on the oblique images captured by the oblique camera and corrects a target lowering position of the head based on the obtained height information, wherein the oblique images include a pre-pickup image captured of the component tape before the components are picked up and a post-pickup image captured of the component tape after the components have been picked up, and the control unit obtains a differential image between the pre-pickup image and the post-pickup image, and calculates the height information using the amount of displacement between the position of the component in the obtained differential image and a reference position.

3. The component mounting device according to claim 1 or 2, wherein the control unit calculates a difference in pixel count (pix), which is an offset amount between the position of the component in the difference image and the reference position, and calculates a height variation (μm) as the height information using the following formula: Height variation (μm) = (difference in pixel count (pix) * resolution (μm / pix)) / cos (tilt angle θ).

4. A component mounting device as described in claim 3, wherein the reference position is the position of the reference point on an oblique image of the reference point captured by the oblique camera when a jig having the reference point is at a reference height.

5. A component mounting device as described in claim 1 or claim 2, wherein if there is a portion in the difference image where the area of ​​the component exceeds an area threshold, or if there is a portion where the position of the component exceeds a distance threshold, the control unit determines the exceeding portion to be noise and removes the exceeding portion from the difference image.

6. The component mounting device according to claim 1, wherein the control unit calculates the amount of positional deviation of the post-mounting image based on the pre-mounting image, and obtains the difference image using the pre-mounting image and the post-mounting image after correcting the amount of positional deviation.

7. The component mounting device of claim 2, wherein the control unit calculates the amount of positional deviation of the post-suction image using the pre-suction image as a reference, and obtains the difference image using the pre-suction image and the post-suction image after correcting the amount of positional deviation.

8. A component mounting device as described in claim 1, further comprising a component recognition camera that captures an image of the component adsorbed to the head and recognizes it, wherein the control unit calculates the amount of deviation due to misalignment of the component due to adsorption based on the image captured by the component recognition camera, and obtains the difference image using the pre-mounting image and the post-mounting image after correcting the amount of deviation.

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