Surface mounting machine

Abstract

To avoid re-photographing.SOLUTION: A surface mounting machine 1 includes a mounting head H that holds an electronic component E and mounts it on a board, a camera 17 that photographs the electronic component held by the mounting head H, a recognition unit 110 that recognizes the state of the electronic component held by the mounting head H on the basis of the image taken by the camera 17, and a control unit 100. The control unit 100 moves the mounting head H such that the electronic component E held by the mounting head H passes above the camera 17, and when the electronic component E held by the mounting head H passes above the camera 17, the control unit 100 changes the photographing conditions and photographs the electronic component E multiple times with the camera 17.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a surface mounter. [Background technology]

[0002] One of the functions of a surface mounter is a component recognition function. The component recognition function recognizes the state of the component held by the mounting head by photographing the component held by the mounting head with a camera. Patent Document 1 is one of the documents that discloses this type of technology. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6482165 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, surface mounters have required high-resolution component recognition cameras. However, in surface mounters, which require high resolution and high speed operation at the same time, insufficient depth of field can be a problem. If the depth of field is insufficient, the camera cannot focus and an image suitable for image recognition cannot be obtained, so the component must be photographed again, which raises concerns about a decrease in takt time. Note that similar issues can occur not only with the depth of field, but also with shooting conditions related to camera lighting, etc. [Means for solving the problem]

[0005] (1) A surface mounter includes a mounting head that holds electronic components and mounts them on a board, a camera that photographs the electronic components held by the mounting head, a recognition unit that recognizes the state of the electronic components held by the mounting head based on the image captured by the camera, and a control unit. The control unit moves the mounting head so that the electronic component held by the mounting head passes above the camera, and when the electronic component held by the mounting head passes above the camera, the control unit changes the shooting conditions and photographs the electronic component multiple times with the camera.

[0006] In this configuration, multiple images are acquired by changing the shooting conditions in one scan, so an image suitable for image recognition can be obtained in one scan. Therefore, retaking the image can be avoided or suppressed. Scanning is the operation of photographing the electronic component while moving the electronic component held by the mounting head above the camera.

[0007] (2) In the surface mounter described in (1) above, the control unit may change the vertical distance from the camera to the electronic component held by the mounting head by moving the mounting head in an upward and downward direction when the electronic component held by the mounting head passes above the camera.

[0008] With this configuration, a focused image can be obtained with one scan, making it possible to obtain an image suitable for image recognition.

[0009] (3) In the surface mounting machine described in (1) or (2) above, the control unit may change the vertical distance from the camera to the electronic component held by the mounting head by moving the mounting head upward when the electronic component held by the mounting head passes above the camera.

[0010] In this configuration, when the electronic components are photographed multiple times with the camera, the mounting head moves in only one direction, upwards. Therefore, compared to when the mounting head moves in two directions, upwards and downwards, the control of the mounting head is simpler and the movement distance of the mounting head is shorter, making it more efficient.

[0011] (4) In the surface mounter described in any one of (1) to (3) above, the recognition unit may recognize a state of an electronic component from an image of a predetermined quality or higher among a plurality of images taken by the camera.

[0012] In this configuration, the state of the electronic component is recognized using an image of a predetermined quality or higher, so that the accuracy of recognition of the state of the electronic component can be improved.

[0013] (5) In the surface mounter described in any one of (1) to (4) above, the control unit may take multiple images of the electronic components held by the mounting head with the camera while updating the cut-out position of the image to the cut-out position of the next image between images. This configuration enables individual exposure, in which exposure is performed for each image during one scan.

[0014] (6) In the surface mounting machine described in any one of (1) to (5) above, the control unit may use the camera to capture an image of an electronic component held by the mounting head when the mounting head passes through a plurality of predetermined passing points.

[0015] With this configuration, the timing of photographing the electronic components can be easily controlled.

[0016] (7) In the surface mounting machine described in (3) above, the control unit may move the mounting head upward so that, when the electronic component held by the mounting head passes above the camera, the position of the underside of the electronic component changes continuously from a position lower than a theoretical reference plane of the electronic component to a position higher than the theoretical reference plane of the electronic component.

[0017] In this configuration, the position of the bottom surface of the electronic component changes continuously from a position lower than the reference surface to a position higher than the reference surface, making it easier to focus.

[0018] (8) In the surface mounter according to any one of (1) to (7) above, a lighting device is provided that irradiates light onto the electronic component when the camera photographs the electronic component, and the control unit may change the photographing conditions by the lighting device and photograph the electronic component multiple times with the camera when the electronic component held by the mounting head passes above the camera. The control unit may change the photographing conditions by changing the intensity of the light irradiated by the lighting device or the direction of the light irradiated by the lighting device.

[0019] With this configuration, multiple images with different lighting conditions can be acquired in one scan, so an optimal, good image can be obtained in one scan, which makes it possible to avoid having to retake the images. Effect of the Invention

[0020] According to the present invention, an image suitable for image recognition can be obtained with one scan, which makes it possible to avoid or reduce the need to retake images, thereby contributing to improving takt time. [Brief description of the drawings]

[0021] [Figure 1] Plan view of surface mounter [Diagram 2] A diagram showing the support structure of the head unit [Diagram 3] Diagram showing the mounting head support structure [Figure 4] Block diagram showing the electrical configuration of a surface mounter [Diagram 5] A diagram showing the photographing operation of an electronic component held by the mounting head. [Figure 6] A diagram showing the photographing operation of an electronic component held by the mounting head. [Figure 7] A diagram showing the photographing operation of an electronic component held by the mounting head. [Figure 8] Diagram showing luminance change when the subject is out of focus [Figure 9] A diagram showing the change in luminance when the subject is in focus [Figure 10]Schematic diagram of part recognition camera [Figure 11] A diagram showing the photographing operation of an electronic component held by the mounting head. [Figure 12] A diagram showing the photographing operation of an electronic component held by the mounting head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] <Embodiment 1> 1. Overall configuration of surface mounter The surface mounter 1 is a device that mounts electronic components E on a substrate P. As shown in Fig. 1, the surface mounter 1 includes a base 11, a transport conveyor 20, a component supply unit 13, a head unit 60, a drive unit 30, and a component recognition camera 17. As an electrical configuration, the surface mounter 1 includes a control unit 100, etc., as shown in Fig. 4.

[0023] In the following description, the transport direction of the substrate P is defined as the X direction (the left-right direction in FIG. 1), and the direction perpendicular to the X direction in a horizontal plane is defined as the Y direction.

[0024] As shown in FIG. 1, the transport conveyor 20 is installed on a base 11, and transports the substrate P in the X direction by a pair of transport belts 21.

[0025] The substrate P is carried into the working position (the position surrounded by the two-dot chain line in FIG. 1) from the upstream side (right side) by the transport conveyor 20. The substrate P carried into the working position is fixed by a clamp or the like (not shown).

[0026] The component supply units 13 are arranged in four locations, two on each side in the X direction on both sides in the Y direction of the transport conveyor 20. A plurality of tape feeders 80 are attached to the component supply units 13 and aligned in the X direction. The tape feeders 80 supply electronic components E to be mounted on the board P.

[0027] The driving device 30 is a device that moves the head unit 60 in a planar direction (X-axis and Y-axis directions) on the base 11. The driving device 30 is composed of an X-axis motor 57, a Y-axis motor 47, an X-axis ball screw 55, a Y-axis ball screw 45, and the like.

[0028] By driving the Y-axis motor 47, the X-beam 51 and the head unit 60 can be moved in the Y direction along the guide rail 42 of the Y-beam 41 (Y-axis servo mechanism).

[0029] By driving the X-axis motor 57, the head unit 60 can be moved in the X direction relative to the X-beam 41 (X-axis servo mechanism).

[0030] Therefore, by controlling the X-axis motor 57 and the Y-axis motor 47 in a composite manner, the head unit 60 can be moved on the base 11 in a planar direction (X-axis and Y-axis directions).

[0031] Furthermore, the X-axis motor 57 and the Y-axis motor 47 each have an encoder, and the position of the head unit 60 can be detected based on the output signal of the encoder.

[0032] The head unit 60 is an in-line type having a plurality of mounting heads H, which perform the operation of mounting electronic components E on a substrate P, mounted in a line.

[0033] 3, each mounting head H has a mounting shaft 64 that is axially long in the vertical direction, and a suction nozzle 65. The suction nozzle 65 is attached to the tip of the mounting shaft 64. Each mounting shaft 64 is configured so that negative pressure is supplied from negative pressure means (not shown) to generate a suction force at the head tip (the tip of the suction nozzle 65).

[0034] As shown in FIG. 3, each mounting head H can be independently raised and lowered with respect to the head unit 60 by a direct acting mechanism (eg, a screw mechanism) 68 using a Z-axis motor 67 as a drive source.

[0035] Further, each mounting head H is provided with an R-axis motor 69. Each mounting head H is capable of independently rotating about the R-axis by being driven by the R-axis motor 69.

[0036] With this configuration, by operating the X-axis motor 57, the Y-axis motor 47, and the Z-axis motor 67 at a predetermined timing, the electronic components E supplied through the tape feeder 80 can be picked up by the mounting head H and mounted at the predetermined mounting position on the printed circuit board P.

[0037] 1 denotes a component recognition camera. The component recognition camera 17 has a two-dimensional image sensor (e.g., a CMOS image sensor) 18. The component recognition camera 17 is fixed on the base 11 with the imaging surface of the image sensor 18 facing upward. The component recognition camera 17 captures an image of the bottom surface of the electronic component E held by the mounting head H from below.

[0038] 4 is a block diagram showing the electrical configuration of the surface mounter 1. The surface mounter 1 has a control unit 100, an image processing unit 110, a recognition unit 120, a storage unit 130, a display unit 140, and an input unit 150. The control unit 100 has a calculation unit 101 and a memory 103.

[0039] The control unit 100 is connected to the X-axis motor 57, the Y-axis motor 47, the Z-axis motor 67, the R-axis motor 69, and the like via a bus.

[0040] The control unit 100 performs the mounting operation of the electronic component E by controlling the X-axis motor 57, the Y-axis motor 47, and the Z-axis motor 67 in accordance with a mounting program stored in the storage unit .

[0041] The component recognition camera 17 is connected to the image processing unit 110. The image processing unit 110 performs predetermined image processing on the image output by the component recognition camera 17. The recognition unit 120 recognizes the state (posture, position angle, etc.) of the electronic component E held by the mounting head H based on the image after image processing.

[0042] The control unit 100 of the surface mounter 1 judges whether the condition of the electronic component E is good or bad based on the recognition result of the recognition unit 120. Then, if the condition of the electronic component E is normal, the mounting operation is performed, and if the condition is abnormal, an error is displayed on the display unit 140 and mounting of the electronic component E by the mounting head H is stopped.

[0043] 3. Scanning with a part recognition camera 5, the surface mounter 1 moves the head unit 60 in the X direction (horizontal direction) so that the electronic component E held by the mounting head H passes above the component recognition camera 17 (within the field of view of the component recognition camera 17). Note that, although an example of moving the mounting head H in the X direction is shown in Fig. 5, the operation of the electronic component E passing above the component recognition camera 17 may be performed by moving the mounting head H in the XY directions.

[0044] Then, when the electronic component E held by the mounting head H passes above the component recognition camera 17, the electronic component E is photographed by the component recognition camera 17.

[0045] Hereinafter, the operation of photographing the electronic component E by the component recognition camera 17 while moving above the component recognition camera 17 will be referred to as scanning.

[0046] If the depth of field of the component recognition camera 17 is insufficient, the camera may not be able to focus properly and may not be able to acquire an image suitable for image recognition in one scan. In such a case, it may be necessary to retake an image of the electronic component E (rescan), which may result in a decrease in takt time.

[0047] In embodiment 1, the field of view size of component recognition camera 17 is greater than the component size of electronic component E, and the optical system (field of view size, component size, head movement speed) is designed so that two or more images can be captured during one scan.

[0048] 6, the control unit 100 moves the mounting head H, which moves in the X direction, in the vertical direction during one scan, thereby taking images of the electronic component E multiple times while moving the electronic component E up and down around the theoretical reference plane S. The theoretical reference plane S is the theoretical height plane (lower surface) of the electronic component E when held by the mounting head H, for example, the height plane (lower surface) of the electronic component E when the nozzle length and component thickness are as designed. The component recognition camera 17 is set to be focused on the theoretical reference plane S.

[0049] In this example, the mounting head H, which moves in the X direction, is moved upward to change the vertical distance D from the component recognition camera 17 to the electronic component E from a distance D1 at the start of the upward movement to a distance D2 at the end of the upward movement.

[0050] As a result, the bottom surface of the electronic component E held by the mounting head H theoretically changes continuously from a position lower than the reference surface S to a position higher than the reference surface S, as shown in FIG.

[0051] The control unit 100 controls the X-direction positions of the head unit 60 and the mounting head H based on the output signal of the encoder of the X-axis motor 57, and captures an image of the electronic component E held by the mounting head H with the component recognition camera 17 each time the mounting head H passes through passing points P1 to P5 above the camera (within the field of view of the component recognition camera 17).

[0052] <Continuous exposure (when continuing exposure during multiple shots)> As shown in FIG. 7, by continuing to expose the image sensor 18 during one scan and irradiating the mounting head H with light in accordance with the timing of the mounting head H passing through the passing points P1 to P5, it is possible to photograph the electronic component E at each of the passing points P1 to P5.

[0053] After scanning, the images EG1 to EG5 are extracted from the image sensor 18, so that five images of the electronic component E can be obtained.

[0054] When the exposure of the image sensor 18 is continued, the images EG1-EG5 of the electronic components E formed on the imaging surface 18A must be set at intervals such that they do not overlap, as shown in Fig. 7. The intervals between the images EG1-EG5 can be adjusted, for example, by the pitch of the passing points P1-P5.

[0055] <Individual exposure (exposure for each shot)> In the case of individual exposure, the control unit 100 needs to update the cut-out position of an image to the position of the next image between shots.

[0056] For example, the first exposure is performed when the mounting head H passes the first passing point P1, and the first image is cut out after the first exposure is completed. After that, between the first and second shooting (the period after the first image is cut out and before the second image is cut out), the image cut-out position is updated from the position of the first image EG1 to the position of the second image EG2. Then, a second exposure is performed when the mounting head H passes the second passing point P2, and after the second exposure is completed, a second image EG2 is extracted.

[0057] In this way, by updating the image cut-out position to the position of the next image between shots, multiple images EG1 to EG5 can be acquired by individual exposure during one scan. In the case of individual exposure, since exposure is performed for each shot, images EG1 to EG5 on imaging surface 18A may overlap. Compared to continuous exposure, individual exposure has the advantage that image sensor 18 can be made smaller.

[0058] In this embodiment, the image processing unit 110 compares the luminance differences and their differential values ​​between adjacent pixels for five images EG1 to EG5 cut out from the image sensor 18, and extracts the image with the largest luminance change between adjacent pixels (the image in focus).

[0059] FIG. 8 shows the luminance change and the luminance difference between adjacent pixels in an out-of-focus image, and FIG. 9 shows the luminance change and the luminance difference between adjacent pixels in an in-focus image.

[0060] It can be seen that an in-focus image has a steeper change in luminance between adjacent pixels than an out-of-focus image.

[0061] The extracted image EG is sent from the image processing unit 110 to the recognition unit 120, and the recognition unit 120 recognizes the state (posture, position, angle, etc.) of the electronic component E held by the mounting head H based on the extracted image EG.

[0062] The head unit 60 is equipped with a plurality of mounting heads H. Therefore, when a plurality of mounting heads H each hold an electronic component E, the control unit 100 moves each mounting head H holding an electronic component E upward during one scan to capture an image of the electronic component E. This makes it possible to obtain a focused image of each electronic component E mounted on each mounting head H.

[0063] 5. Effects of the First Embodiment In the first embodiment, the vertical distance D from the component recognition camera 17 to the electronic component E is changed as a photographing condition for the electronic component E. With this configuration, a focused image can be obtained with one scan, so that retaking of photographs can be avoided or suppressed. This contributes to improving the takt time.

[0064] In particular, in this embodiment, the position of the lower surface of the electronic component E changes continuously from a position lower than the reference surface S to a position higher than the reference surface S, so that it is easy to achieve focus.

[0065] Furthermore, during one scan, the mounting head H moves in only one direction, the upward direction. Compared to the case where the mounting head H moves in two directions, the upward and downward directions, the control of the mounting head H is simpler and the movement distance of the mounting head H is shorter, which is more efficient.

[0066] <Embodiment 2> Next, a second embodiment will be described with reference to Fig. 10 and Fig. 11. Unlike the first embodiment, the second embodiment changes the image capturing conditions for the electronic component E by changing the intensity and / or direction of light emitted from a plurality of light sources 175. Note that the same reference numerals are used for parts common to the first embodiment, and detailed description thereof will be omitted.

[0067] 10 is a schematic diagram of a component recognition camera 170. The component recognition camera 170 has a camera body 171, a lens 172, an illumination device 173, and a housing 177.

[0068] The lighting device 173 has a plurality of light sources 175, and is attached to the upper side of the housing 177. The control unit 100 can arbitrarily change the direction and intensity of the light irradiated from the light sources 175 toward the electronic component E by controlling the light sources 175.

[0069] In the second embodiment, as shown in FIG. 11, a plurality of images are acquired during one scan by changing the direction of light irradiated from a light source 175 to an electronic component E.

[0070] Specifically, the first time, the electronic component E is photographed by irradiating it with light from the side, and the second time, the electronic component E is photographed by irradiating it with light from the same axial direction of the camera 170. Then, the third time, the electronic component E is photographed by irradiating it with light from an intermediate position between the first and second times.

[0071] In the second embodiment, a set of three images with different lighting directions can be acquired in one scan, making it possible to significantly reduce mounting time.

[0072] 12, the intensity of the light irradiated from the light source 175 to the electronic component E may be changed during one scan, and the electronic component E may be photographed multiple times. The change in the light intensity may be performed instead of or in combination with changing the direction of the light. In addition, in FIG. 12, the number of arrows indicates the light intensity.

[0073] <Other embodiments> (1) In the first embodiment, the mounting head H is moved only in the upward direction during one scan. However, this is not limited to this, and the mounting head H may be moved in the vertical direction or in the downward direction during one scan.

[0074] (2) In the first embodiment, the image with the largest luminance change between adjacent pixels is extracted from the five images captured during one scan to recognize the state of the electronic component E. The state of the electronic component E may be recognized by extracting, from the five images, the image with the luminance change between adjacent pixels equal to or greater than a predetermined value (i.e., an image with a quality equal to or greater than a predetermined value).

[0075] (3) In the second embodiment, the illumination device 173 is built into the component recognition camera 170. However, the illumination device 173 may be provided separately from the component recognition camera 170. [Explanation of symbols]

[0076] 1 Surface mount machine 17, 170 Parts recognition camera 60 Head Unit H Mounting head 100 Control section 120 Recognition part 173 Lighting Equipment

Claims

1. A surface mount machine, a mounting head that holds electronic components and mounts them on a board; a camera for photographing an electronic component held by the mounting head; a recognition unit that recognizes a state of the electronic component held by the mounting head based on the image captured by the camera; A control unit, The control unit is moving the mounting head so that the electronic components held by the mounting head pass above the camera; When an electronic component held by the mounting head passes above the camera, the electronic component is photographed multiple times by the camera under different photographing conditions.

2. 2. The surface mounter according to claim 1, the control unit changes the vertical distance from the camera to the electronic component held by the mounting head by moving the mounting head in an upward and downward direction when the electronic component held by the mounting head passes above the camera.

3. 3. The surface mounter according to claim 2, the control unit changes the vertical distance from the camera to the electronic component held by the mounting head by moving the mounting head upward when the electronic component held by the mounting head passes above the camera.

4. 2. The surface mounter according to claim 1, The recognition unit recognizes the state of an electronic component from an image of a predetermined quality or higher among a plurality of images captured by the camera.

5. 2. The surface mounter according to claim 1, The control unit updates the cut-out position of the image to the cut-out position of the next image between shots, and captures images of the electronic component held by the mounting head multiple times with the camera.

6. 2. The surface mounter according to claim 1, The control unit causes the camera to capture an image of an electronic component held by the mounting head each time the mounting head passes through a plurality of preset passing points.

7. 4. The surface mounter according to claim 3, The control unit moves the mounting head upward so that, when the electronic component held by the mounting head passes above the camera, the underside of the electronic component changes continuously from a position lower than a theoretical reference plane of the electronic component to a position higher than the theoretical reference plane of the electronic component.

8. 2. The surface mounter according to claim 1, a lighting device that irradiates light onto the electronic component when the camera photographs the electronic component; The control unit changes shooting conditions using the lighting device and shoots the electronic component multiple times with the camera when the electronic component held by the mounting head passes above the camera.

9. 9. The surface mounter according to claim 8, The control unit changes the shooting conditions by changing the intensity of the light emitted by the lighting device and / or the direction of the light emitted by the lighting device.

Images