(19)
(11)EP 2 699 069 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
19.02.2014 Bulletin 2014/08

(21)Application number: 12771402.0

(22)Date of filing:  06.03.2012
(51)International Patent Classification (IPC): 
H05K 13/04(2006.01)
H05K 13/08(2006.01)
(86)International application number:
PCT/JP2012/055716
(87)International publication number:
WO 2012/140975 (18.10.2012 Gazette  2012/42)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 13.04.2011 JP 2011089551

(71)Applicant: Fuji Machine Mfg. Co., Ltd.
Chiryu-shi Aichi 472-8686 (JP)

(72)Inventors:
  • KAWAI, Hidetoshi
    Chiryu-shi, Aichi 472-8686 (JP)
  • AKATSUKA, Ryota
    Chiryu-shi, Aichi 472-8686 (JP)

(74)Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser 
Leopoldstrasse 4
80802 München
80802 München (DE)

  


(54)COMPONENT-MOUNTING DEVICE


(57) Before starting production, measure the deviation amount of the recognized position of multiple components A to D being held by multiple suction nozzles 21 and memorize that measurement data using a memorizing means; then, during production, correct the deviation of the recognized position of components A to D being held on each suction nozzle 21 by reading the data for the recognized position deviation amounts from said memorizing means. For the measurement of the deviation amount of the recognized position it is preferable to, before starting production, to take an image of a component being held on suction nozzle 21 with the center of suction nozzle 21 and the center of the camera field of view aligned and to image process this image to recognize the position of the component; and also to move suction nozzle 21 to the position where the image is to be taken during production and to take an image of the component with the camera and vision process the image to recognize the position of the component; then to calculate the recognized position deviation amount as the difference between the distance that suction nozzle 21 was moved and the distance separating the two recognized position points.




Description

TECHNICAL FIELD



[0001] The present invention relates to a component mounter which takes images of components being held on suction nozzles using a camera, recognizes the pickup position of said components using image processing, and mounts the components on a circuit board.

BACKGROUND TECHNOLOGY



[0002] For example, with rotary head type (revolving head type) electronic component mounters, as disclosed in Prior Art 1 (Japanese published unexamined patent application number 2010-199630), in order to reduce the number of times images are taken of components being held on suction nozzles and thereby improve productivity, multiple components each being held by a suction nozzle of a rotary head equipped with multiple suction nozzles are gathered within the same field of view of a camera and an image taken of all the components at the same time; the signal of this image is then processed and the pickup position of each of the multiple components is recognized, and each component is then mounted on the circuit board considering the deviation of the pickup position (that is, the deviation between the center of the component and the center of the suction nozzle).

PRIOR ART REFERENCES


PRIOR ART



[0003] Prior Art 1: Japanese published unexamined patent application number 2010-199630

BRIEF SUMMARY OF THE INVENTION


PROBLEM SOLVED BY INVENTION



[0004] With the electronic component mounter from Prior Art 1 above, a single image of all the components is taken using a camera, with the multiple components held on multiple suction nozzles illuminated by a dome-shaped (bowl-shaped) light source from below. With this mounter, the configuration is such that the center of the camera field of view (image center) and the center of the light source are aligned; however, when gathering multiple components into the same camera field of view and taking a single image of all the components, the image is taken such that the position of each component is misaligned with the center of the camera field of view (center of the light source).

[0005] If a component of which an image is to be taken is a BGA-type component, the pickup position of the component is recognized by recognizing the bumps arranged in specific positions on the bottom surface of the component; however, because the position of the component when the image is taken is misaligned with the center of the camera field of view (center of the light source), the light and dark condition (shading) of the bumps due to the illumination changes based on the distance from the center of the field of view (the exposure angle with respect to the light source); as a result, the recognized position of the component of which an image is taken by the camera is deviated. Also, if the height position from the light source at which the image is taken changes, the exposure angle with respect to the light source changes, and the recognized position of the component is deviated.

[0006] Also, there are cases in which the recognized position of the component is deviated if the component type is changed. For example, when recognizing the position of curved sections of components such as BGA-type components with bumps or the electrodes of chip capacitors, the light and dark condition (due to the light source) of the sections used for recognition changes based on the size of the curvature, and the recognized position of the component is deviated. If the recognized position of the component is deviated, the mounting position accuracy of the component to be mounted on the circuit board deteriorates by that amount.

[0007] With respect to this, for the problem to be solved by this invention, what is proposed is an electronic component mounter equipped with a function for correcting the deviation of the recognized position of a component caused by the effect of the light source.

MEANS OF SOLVING THE PROBLEM



[0008] In order to solve the above problem, the invention from claim 1 is equipped with a camera to take images of components being held on suction nozzles illuminated by a light source from below and an image processing means to process the image signal of said camera in order to recognize the pickup position of the components; said invention being an electronic component mounter which mounts said components on a circuit board considering the deviation of the pickup position of said components with respect to said suction nozzles based on the recognition results of the image processing means; the mounter being configured such that it is equipped with a recognized position deviation correction means for correcting the deviation in the recognized position of said components due to the positional relationship between the component and the light source which considers the deviation in the recognized position of said components of which an image is taken by said camera caused by the changing light and dark condition of the component (due to the light source) due to the positional relationship between the light source and the components being held by said suction nozzles.

[0009] With this configuration, even if a deviation arises in the recognized position of a component due to changes in the light and dark condition (shading) of the component (due to the light source) due to the positional relationship between the light source and the components being held by the suction nozzles, correction of the recognized position deviation of the component due to the positional relationship of the light source and the component can be performed using the recognized position deviation correction means; therefore, the mounting accuracy when mounting the component on the circuit board can be improved.

[0010] However, there are cases in which an image is taken by the camera of a single component being held by a single suction nozzle and the pickup position of that component recognized. In this case, it is possible to take the image with the single component being held by a single suction nozzle in the center of the camera field of view (center of the light source). Therefore, when the component and the center of the camera field of view are aligned, virtually no deviation arises in the recognized position of the component due to the effects of the light source, which means that there is no need to correct for the deviation in the recognized position of the component; however, when the component and the center of the camera field of view are not aligned, a deviation does arise in the recognized position of the component due to the effects of the light source, which means that, by using the present invention, it is possible to correct for the deviation in the recognized position of the component due to the positional relationship of the light source and the component.

[0011] Also, when gathering multiple components each being held by one of multiple suction nozzles into the same camera field of view and taking a single image of all the components, because it is impossible to take an image with each of the components in the center of the camera field of view (center of the light source) at the same time, a deviation arises in the recognized position of the components which are misaligned with the center of the camera field of view (center of the light source). Therefore, when taking a single image of multiple components, by using the present invention, it is possible to correct for the deviation in the recognized position of the multiple components of which a single image is taken, this making it possible to mount the multiple components for which a single image is taken on a circuit board with high accuracy.

[0012] Also, it is preferable for the present invention to be equipped with a recognized position deviation amount measuring means for measuring the amount of deviation in the recognized position of the components being held by suction nozzles, and a memorizing means for memorizing the measured recognized position deviation amount data which is measured by the recognized position deviation amount measuring means; said recognized position deviation amount correction means correcting said deviation in the recognized position of the components being held on the suction nozzles by importing said data for the recognized position deviation amount from said memorizing means during production. By doing this, it is possible to measure the amount of deviation in the recognized position of the components due to the effects of the light source and to memorize this amount using the memorizing means before starting production, and then subsequently it is possible to accurately correct for the deviation in the recognized position of components due to the effects of the light source during production based on the recognized position deviation amount data memorized in the memorizing means,

[0013] Specifically, it is preferable to have a configuration in which the center of the camera field of view and the center of the light source are aligned, and, before starting production, to take an image of a component being held on a suction nozzle with the center of the suction nozzle and the center of the camera field of view aligned and to image process this image to recognize the position of the component; and also to move the suction nozzle to the position where the image is to be taken during production and to take an image of the component with the camera and vision process the image to recognize the position of the component; then to calculate said recognized position deviation amount as the difference between the distance that the suction nozzle was moved and the distance separating the two recognized position points. By doing this, it is possible to accurately measure the recognized position deviation amount before starting production.

[0014]  In other words, it is preferable to create a memorizing means for memorizing a table containing recognized position deviation amounts as parameters which represent the positional relationship between a component being held on a suction nozzle and the light source; and to read the data for said recognized position deviation amount based on the positional relationship between the component being held on a suction nozzle and said light source from said table memorized in said memorizing means during production, and then to correct said deviation of the recognized position of the component being held on the suction nozzle. By doing this, the process for measuring the recognized position deviation amount before starting production can be omitted, therefore productivity is improved by this amount.

[0015] In this case, as in claim 6, it is preferable for a said table to be memorized for each type of component in said memorizing means, and during production the data for the said recognized position deviation amount based on the positional relationship between said component being held on a suction nozzle and said light source to be read from a table selected based on the component type at that time which is among the said tables for each component type memorized in the said memorizing means; and to use this data to correct the deviation in the recognized position of the component being held by the suction nozzle. By doing this, it is possible to accurately correct the deviation in the recognized position of various types of components.

BRIEF DESCRIPTION OF THE DRAWINGS



[0016] 

[FIG. 1] FIG. 1 is a perspective view showing the configuration of the modular component mounting system from embodiment 1 of the present invention.

[FIG. 2] FIG. 2 is a perspective view showing the XY-axis movement device which moves the mounting head in the X and Y directions.

[FIG. 3] FIG. 3 is a perspective view showing the camera and mounting head attachment configuration with respect to the second X-axis slide of the X-axis slide mechanism.

[FIG. 4] FIG. 4 is a cross-section view showing X-axis slide mechanism.

[FIG. 5] FIG. 5 is a perspective view showing the Y-axis slide mechanism and the X-axis slide mechanism configuration.

[FIG. 6] FIG. 6 is a cross-section view showing the positional arrangement of the lens, light source, and camera used for recognizing components.

[FIG. 7] FIG. 7 is a diagram to describe the processing procedure for measuring the deviation amount of the recognized position of components held on suction nozzles from embodiment 1 (part 1).

[FIG. 8] FIG. 8 is a diagram to describe the processing procedure for measuring the deviation amount of the recognized position of components held on suction nozzles from embodiment 1 (part 2).

[FIG. 9] FIG. 9 is a diagram to describe the processing procedure for measuring the deviation amount of the recognized position of components held on suction nozzles from embodiment 1 (part 3).

[FIG. 10] FIG. 10 is a diagram to describe the processing procedure for measuring the deviation amount of the recognized position of components held on suction nozzles from embodiment 1 (part 4).

[FIG. 11] FIG. 11 is a diagram to describe the processing procedure for measuring the deviation amount of the recognized position of components held on suction nozzles from embodiment 1 (part 5).

[FIG. 12] FIG. 12 is a flowchart to show the processing flow of the program for measuring the recognized position deviation amount of embodiment 1 (part 1).

[FIG. 13] FIG. 13 is a flowchart to show the processing flow of the program for measuring the recognized position deviation amount of embodiment 1 (part 2).

[FIG. 14] FIG. 14 is a flowchart to show the processing flow of the production program of embodiment 1.

[FIG. 15] FIG. 15 is a diagram to show conceptually the data tables for the recognized position deviation amounts of embodiment 2.


MODES FOR CARRYING OUT THE INVENTION



[0017] The following describes two modes for carrying out the invention, embodiment 1 and embodiment 2.

Embodiment 1



[0018] The following uses FIG. 1 to FIG. 14 to describe specific embodiment 1 of the present invention which is a modular component mounting system.

[0019] First, the following describes the configuration of the modular component mounting system using FIG. 1.
Multiple rotary head type (revolving head type) mounting modules 12 (component mounters) are exchangeably arranged next to each other on a base 11 of the modular component mounting system in the conveyance direction of the circuit boards. Each mounting module 12 has: feeders 14 (such as tape feeders), circuit board conveyance device 15, camera 16 for taking images of components, component mounting device 17, and other items on main bed 13; and display device 19 (such as an LCD display or CRT), and operation section 20 (such as operation buttons) on the front section of upper frame 18. In each mounting module 12, circuit boards are conveyed sequentially using circuit board conveyance device 15 and components are mounted on the circuit boards using component mounting device 17.

[0020] Next, the following describes the configuration of component mounting device 17 using FIG. 2 to FIG. 5.

[0021] Here, FIG. 2 is a perspective view showing the XY-axis movement device which moves mounting head 22 in the X and Y directions; FIG. 3 is a perspective view showing the attachment configuration of mounting head 22 with respect to the second X-axis slide 42 of X-axis slide mechanism 23; FIG. 4 is a cross-section view showing the configuration of X-axis slide mechanism 23; FIG. 5 is a perspective view showing Y-axis slide mechanism 24 and the configuration of X-axis slide mechanism 23.

[0022] As shown in FIG. 2 and FIG. 3, component mounting device 17 consists of items such as rotary type (revolving type) mounting head 22 which has multiple exchangeable suction nozzles 21; X-axis slide mechanism 23 to move this mounting head 22 in the circuit board conveyance direction (hereafter this direction is defined as the "X-axis direction"); Y-axis slide mechanism 24 to move this X-axis slide mechanism 23 together with mounting head 22 in the Y-axis direction (the direction perpendicular to the circuit board conveyance direction); and nozzle raising and lowering mechanism 53 to raise and lower suction nozzles 21 of mounting head 22 when performing component pickup operation and mounting operation.

[0023] Y-axis slide mechanism 24 is configured such that Y-axis slide 33 is slid in the Y-axis direction along Y-axis guides 34 by the rotational movement of Y-axis ball screw 32 which is turned by Y-axis motor 31 which is attached to the upper frame 18 side of mounting module 12 (refer to FIG. 5).

[0024] Then, as shown in FIG. 4 and FIG. 5, X-axis slide mechanism 23 is configured such that it has a two-level slide mechanism consisting of the two X-axis slides 41 and 42, and the first X-axis slide 41 is slid in the X-axis direction along first guides 43 by the rotational movement of first X-axis ball screw 45 which is turned by first X-axis motor 44, wherein the first X-axis motor 44 and first guides 43 for guiding the first X-axis slide 41 in the X-axis direction are attached to supporting board 33a which is secured perpendicularly to Y-axis slide 33. It is also configured such that the second X-axis slide 42 is slid in the X-axis direction along second guides 46 by the rotational movement of second X-axis ball screw 48 which is turned by second X-axis motor 47, wherein the second X-axis motor 47 and second guides 46 for guiding the second X-axis slide 42 in the X-axis direction are attached to first X-axis slide 41.

[0025] As shown in FIG. 3, mounting head 22 is configured such that the circumference of the center axis of said mounting head 22 is rotated intermittently based on the pitch angle between suction nozzles 21 arranged on the head (pitch movement is performed) by motor 54 which is for rotating the head; wherein mounting head 22 is assembled to be able to be rotated on holding bracket 51 which is secured to second X-axis slide 42. On this mounting head 22, multiple nozzle holders 55 which hold pickup nozzles 21 are assembled so that they can be raised and lowered in the up/down direction (Z-direction); and, during component pickup and placement operation, a single nozzle holder 55 (suction nozzle 21) which is positioned at a specific component pickup and placement station is raised and lowered by nozzle raising and lowering mechanism 53 which has power provided by nozzle raising and lowering motor 52 (Z-axis motor).

[0026] Then, as shown in FIG. 6, camera 16 for recognizing components is attached facing upwards to main bed 13 of mounting module 12 via supporting frame 61. The configuration is such that lens 62 is arranged directly above this camera 16; dome-shaped (bowl-shaped) light source 64 is attached directly above this lens 62 via box-shaped section 63; and the center of the field of view of camera 16 and the center of light source 64 are aligned. Multiple light-emitting elements 65 (such as LEDs) are arranged on the inner surface of the dome section of light source 64 such that, when images of components being held on suction nozzles 21 are taken by camera 16, the components are illuminated from below by light source 64. The upper surface of light source 64 is covered by transparent cover 66 through which the light passes.

[0027]  Items such as X-axis slide mechanism 23, Y-axis slide mechanism 24, first X-axis motor 44 for moving nozzle raising and lowering mechanism 53, second X-axis motor 47, Y-axis motor 31, nozzle raising and lowering motor 52 (Z-axis motor), and motor 54 for rotating the head are controlled by the control device (computer) of mounting module 12. This control device of mounting module 12 functions as the image processing means which processes the image signal of camera 16 and recognizes the pickup position of components.

[0028] During operation of mounting module 12, each time a component supplied from a feeder 14 is picked up by a suction nozzle 21, mounting head 22 rotates only by the pitch angle amount (the movement pitch amount) of the arranged suction nozzles 21, and then repeats this so-called pickup operation for a component supplied from a feeder 14 using the next suction nozzle 21; after multiple suction nozzles 21 have each picked up a component, mounting head 22 is moved to the position for taking images during production at which a single image is to be taken for all components (the position in which the center of mounting head 22 is aligned with the center of the field of view of camera 16); then, as shown in FIG. 11, multiple suction nozzles 21 each holding one of the multiple components (A to D) are gathered in the field of view of camera 16 and a single image taken; then the image signal of camera 16 is processed, the pickup position of each component recognized, and the deviation of the pickup position of each component (the misalignment between the center of the component and the center of the pickup nozzle 21) is calculated; as well as this, mounting head 22 is moved directly above the mounting position of the components on the circuit board, and then each component is mounted on the circuit board considering the deviation in the pickup position of the components being held by each of the suction nozzles 21.

[0029] However, when gathering multiple components A to D within the field of vision of camera 16 and taking a single image of all the components after illuminating the multiple components A to D being held on multiple suction nozzles 21 from below using light source 64 (as shown in FIG. 11), this means that the image is taken with the position of each of the components A to D misaligned with the center of the field of view of camera 16 (the center of light source 64). If the components A to D of which an image is to be taken are BGA-type components, the pickup position of each of the components A to D is recognized by recognizing the bumps arranged in specific positions on the bottom surface of the component; however, because the position of each of the components A to D when the image is taken is misaligned with the center of the camera field of view (center of the light source), the light and dark condition (shading) of the bumps due to the illumination changes based on the distance from the center (the exposure angle with respect to the light source); as a result, the recognized position of each component A to D taken by the camera is deviated. Also, if the height position from the light source at which the image is taken changes, the exposure angle with respect to the light source changes, and the recognized position of each component A to D is deviated.

[0030] Also, there are cases in which the recognized position of each component A to D is deviated if the type of each component A to D is changed. For example, when recognizing the position of curved sections of components such as BGA-type components with bumps or the electrodes of chip capacitors, the light and dark condition (due to the light source) of the sections used for recognition changes based on the size of the curvature, and the recognized position of each component A to D is deviated. If the recognized position of each component A to D is deviated, the mounting position accuracy of each component A to D to be mounted on the circuit board deteriorates by that amount.

[0031] As a countermeasure to this, in embodiment 1 of the present invention, the control device of mounting module 12 is used to do the following: before starting production, by running the program for measuring the recognized position deviation amount from FIG. 12 and FIG. 13 described below, and by measuring before starting production each deviation amount of the recognized position of each of the multiple components A to D being held by multiple suction nozzles 21, then memorizing the measurement data in a memorizing means such as a hard disk or RAM, and then after that, by running the production program from FIG. 14 described below during production; correct the deviation in the recognized position of components A to D each being held by a suction nozzle 21 by reading the measurement data of the recognized position deviation amount from said memorizing means during production. Below uses each program flowchart from FIG. 12 to FIG. 14 to describe a control example when the quantity of suction nozzles on mounting head 22 is four.

Recognized position deviation amount measurement program



[0032] The recognized position deviation amount measurement programs from FIG. 12 and FIG. 13 are run before starting production using the control device of mounting module 12, and this performs the role of the recognized position deviation amount measurement means which measures the deviation amount of the recognized position of each of the components A to D being held by the four suction nozzles 21.

[0033] When this program is started, first, in step 101, each of the components A to D is picked up by the four suction nozzles 21. Then, continuing to step 102, as shown in FIG. 7, mounting head 22 is moved so that the center of the first suction nozzle 21 is aligned with the center of the field of view of camera 16 (the center of light source 64); and, in the next step 103, camera 16 takes an image of component A being held by said first suction nozzle 21 as it is illuminated from below by light source 64. Then, continuing to step 104, the image signal from camera 16 is processed and the pickup position (Xa1, Ya1) of component A being held on the first suction nozzle 21 is recognized and memorized using RAM or other such means. Here, the pickup position (Xa1, Ya1) of recognized component A is the center position of component A (hereafter the same). With this, the position of the sections of component A to be recognized (for example: in the case of a BGA-type component, the bumps; in the case of a chip capacitor, the terminals) are recognized, and the center position of component A is taken as the pickup position (Xa1, Ya1) (hereafter the same).

[0034] Then, continuing to step 105, as shown in FIG. 8, mounting head 22 is moved so that the center of the second suction nozzle 21 is aligned with the center of the field of view of camera 16 (the center of light source 64); and, in the next step 106, camera 16 takes an image of component B being held by said second suction nozzle 21 as it is illuminated from below by light source 64. Then, continuing to step 107, the image signal from camera 16 is processed and the pickup position (Xb1, Yb1) of component B being held on the second suction nozzle 21 is recognized and memorized using RAM or other such means.

[0035] Then, continuing to step 108, as shown in FIG. 9, mounting head 22 is moved so that the center of the third suction nozzle 21 is aligned with the center of the field of view of camera 16 (the center of light source 64); and, in the next step 109, camera 16 takes an image of component C being held by said third suction nozzle 21 as it is illuminated from below by light source 64. Then, continuing to step 110, the image signal from camera 16 is processed and the pickup position (Xc1, Yc1) of component C being held on the third suction nozzle 21 is recognized and memorized using RAM or other such means.

[0036] Then, continuing to step 111, as shown in FIG. 8, mounting head 22 is moved so that the center of the fourth suction nozzle 21 is aligned with the center of the field of view of camera 16 (the center of light source 64); and, in the next step 112, camera 16 takes an image of component D being held by said fourth suction nozzle 21 as it is illuminated from below by light source 64. Then, continuing to step 113, the image signal from camera 16 is processed and the pickup position (Xd1, Yd1) of component D being held on the fourth suction nozzle 21 is recognized and memorized using RAM or other such means.

[0037] As given above, after recognizing each of the pickup positions of components A to D being held by the four suction nozzles 21, continuing to step 114 of FIG. 13, mounting head 22 is moved to the position for taking pictures during production which is the position for taking pictures of all the components at the same time (the position at which the center of mounting head 22 is aligned with the center of the field of view of camera 16); and, as shown in FIG. 11, the four components A to D being held on the four suction nozzles 21 are all gathered in the field of view of camera 16. Then, continuing to step 115, camera 16 takes a single image of all the components A to D being held by the four suction nozzles 21 while they are illuminated from below by light source 64; then, in the next step 116, the image signal from camera 16 is processed and the pickup positions of the four components A to D (Xa2, Ya2), (Xb2, Yb2), (Xc2, Yc2), (Xd2, Yd2) being held by the four suction nozzles 21 are recognized and memorized using RAM or other such means.

[0038] For the above, it is also acceptable to perform the processing for steps 114 to 116 (processing to recognize the pickup position of each component A to D after taking a single image of all four components A to D) before the processing for steps 102 to 113 (processing to recognize the pickup position of each of the components A to D after taking an individual image of each of those said components at the center of the field of view of camera 16).

[0039] Then, continuing to step 117, the distance (ΔXa1.a2, ΔYa1.a2) between the two recognized positions of component A (Xa1, Ya1), (Xa2, Ya2) being held on the first suction nozzle 21 is calculated.





[0040] Also, the movement distance of the first suction nozzle 21 (ΔX1, ΔY1) is calculated. If suction nozzle 21 is moved without rotating mounting head 22, the movement distance of suction nozzle 21 and the movement distance of mounting head 22 will be the same (hereafter the same).

[0041] And, the difference between the distance separating the two recognized positions of component A being held by first suction nozzle 21 and the movement distance of said suction nozzle 21 is calculated as the recognized position deviation amount of said component A and memorized using the memorizing means.





[0042] Next, continuing to steep 118, along with calculating the distance (ΔXb1.b2, ΔYb1.b2) between the two recognized positions of component B (Xb1, Yb1), (Xb2, Yb2) being held on the second suction nozzle 21, the movement distance of the second suction nozzle 21 (ΔX2, ΔY2) is calculated; the difference between these two distances is calculated as the recognized position deviation amount of component B and memorized using the memorizing means.



Next, continuing to step 119, along with calculating the distance (ΔXc1.c2, ΔYc1.c2) between the two recognized positions of component C (Xc1, Yc1), (Xc2, Yc2) being held on the third suction nozzle 21, the movement distance of the third suction nozzle 21 (ΔX3, ΔY3) is calculated; the difference between these two distances is calculated as the recognized position deviation amount of component C and memorized using the memorizing means.

Next, continuing to step 120, along with calculating the distance (ΔXd1.d2, ΔYd1.d2) between the two recognized positions of component D (Xd1, Yd1), (Xd2, Yd2) being held on the fourth suction nozzle 21, the movement distance of the fourth suction nozzle 21 (ΔX4, ΔY4) is calculated; the difference between these two distances is calculated as the recognized position deviation amount of component D and memorized using the memorizing means.




Production programs



[0043] The production program for FIG. 14 is run during production by the control device of mounting module 12. When this program is started, first, in step 201, each of the components A to D is picked up by the four suction nozzles 21. Next, continuing to step 202, mounting head 22 is moved to the position for taking pictures during production which is the position for taking pictures of all the components at the same time (the position at which the center of mounting head 22 is aligned with the center of the field of view of camera 16); and, as shown in FIG. 11, the four components A to D being held on the four suction nozzles 21 are all gathered in the field of view of camera 16.

[0044] Then, continuing to step 203, camera 16 takes a single image of all the components A to D being held by the four suction nozzles 21 while they are illuminated from below by light source 64; then, in the next step 204, the image signal from camera 16 is processed and the pickup positions of the four components A to D (Xa3, Ya3), (Xb3, Yb3), (Xc3, Yc3), (Xd3, Yd3) being held by the four suction nozzles 21 are recognized.

[0045] Next, continuing to step 205, each of the recognized positions for the four components A to D (Xa3, Ya3), (Xb3, Yb3), (Xc3, Yc3), (Xd3, Yd3) are corrected based on the following equations using the measurement data of the recognized position deviation amounts read from the memorizing means.
  1. (1) Recognized position of component A after correction (Xa4, Ya4)



  2. (2) Recognized position of component B after correction (Xb4, Yb4)



  3. (3) Recognized position of component C after correction (Xc4, Yc4)



  4. (4) Recognized position of component D after correction (Xd4, Yd4)





[0046] This step 205 processing performs the role of the recognized position deviation correction means mentioned in the scope of the patent claims.

[0047] Next, continuing to step 206, mounting head 22 is moved directly above the mounting position of the components on the circuit board, and then each component A to D is mounted on the circuit board considering the deviation in the pickup position of the components A to D being with respect to each of the suction nozzles 21.

[0048] Next, continuing to step 207, a judgment is made as to whether production has been completed, and if production has not been completed, the process returns to step 201 above. In this way, processing from steps 201 to 206 is run repeatedly during production. Next, in step 207 above, when production is judged to have been completed, the program finishes.

[0049]  According to embodiment 1 described above, by measuring the amount of deviation in the recognized position of components due to the effects of the light source, and then memorizing that measurement data using a memorizing means before production, the measurement data for the recognized position deviation amount can be read from said memorizing means during production; this makes it possible to accurately correct for the deviation in the recognized position of components due to the effects of the light source based on the recognized position deviation amount data memorized in the memorizing means, and to improve the mounting position accuracy of the components mounted on the circuit board.

[0050] However, there are cases in which an image is taken by camera 16 of a single component being held by a single suction nozzle and the pickup position of that component recognized. In this case, it is possible to take the image with the single component being held by a single suction nozzle in the center of the camera 16 field of view (center of the light source). Therefore, when the component and the center of the camera 16 field of view are aligned, virtually no deviation arises in the recognized position of the component due to the effects of the light source, which means that there is no need to correct for the deviation in the recognized position of the component; however, when the component and the center of the camera 16 field of view are not aligned, a deviation does arise in the recognized position of the component due to the effects of the light source, which means that, by using the present invention, it is possible to correct for the deviation in the recognized position of the component due to the positional relationship of light source 64 and the component.

[0051] Furthermore, in step 205 of the production program from FIG. 14 mentioned above, correction of the recognized position of the four components A to D (Xa3, Ya3), (Xb3, Yb3), (Xc3, Yc3), (Xd3, Yd3) was performed using the measurement data of the recognized position deviation amounts read from the memorizing means; however, when mounting the same type of component at positions A to D using suction nozzles 21, it is also acceptable for a specific recognized position deviation amount for a component being held by a suction nozzle 21 to be used as a representative value, and by using this specific recognized position deviation amount for a component being held by a suction nozzle 21, the recognized position deviation amount for the other components being held by suction nozzles 21 can be calculated. This calculation method is described below.









[0052] If component B is arranged in a position rotated by angle θAB (=90°) with respect to component A, component B Y-direction recognized position deviation amounts CX2, CY2 are calculated using component A X-direction recognized position deviation amounts CX1, CY1 according to the equations below.





[0053] In this way, it is acceptable to calculate the recognized position deviation amount of the other components being held on suction nozzles 21 by using the recognized position deviation amount of a specific component being held on a suction nozzle 21.

Embodiment 2



[0054] In embodiment 1 above, the amount of deviation in the recognized position of the components due to the effects of the light source was measured and this measurement data memorized using the memorizing means before starting production; however, in embodiment 2 of the present invention as shown in FIG. 15, a table containing recognized position deviation amounts as parameters which represent the positional relationship between a component being held on suction nozzles 21 and the light source 64 is memorized for each component type in a memorizing means, and correction is performed for the deviation in the recognized position of the component being held by a suction nozzle 21 by reading the data for the recognized position deviation amount based on the positional relationship between the components being held on suction nozzles 21 and light source 64 for the component type from a table selected based on the component type at that time which is among the tables for each component type memorized in the said memorizing means during production.

[0055] Here, it is acceptable to calculate the table data using mounting module 12 in the same method as in embodiment 1 above; or, it is acceptable to measure not actual components but jigs which simulate actual components; or, it is acceptable to make theoretical calculations considering the special characteristics of the deviation in the recognized position of a component.

[0056] This embodiment 2 uses the image taking position (R) and image taking height (Z) as parameters of the positional relationship between components being held on suction nozzles 21 and light source 64. The distance from the center of light source 64 to the sections of a component to be recognized (for example: in the case of a BGA-type component, the bumps; in the case of a chip capacitor, the terminals) is used for image taking position (R). The image taking height (Z) is the height from a reference position (for example, the position of camera 16) to the component. Also, the diameter or curvature of the sections of a component to be recognized (for example: in the case of a BGA-type component, the diameter of the bumps; in the case of a chip capacitor, the curvature of the terminals) are used as component type parameters.

[0057] In this embodiment 2, during production, after taking a single image of multiple components being held on multiple suction nozzles 21 at the same time, the deviation in the recognized position (X, Y) of the multiple components being held on multiple suction nozzles 21 is corrected by reading the data for the recognized position deviation amount (Δx, Δy) according to the image taking position (R) and image taking height (Z) from the selected from a table based on the diameter of the bumps (or curvature of the electrodes) of the component at that time, the table being selected from the multiple tables memorized in the memorizing means.

[0058]  With embodiment 2 described above, the process for measuring the recognized position deviation amount before starting production can be omitted, therefore productivity is improved by this amount.

[0059] Furthermore, the present invention is not limited to a modular type component mounting system such as that shown in FIG. 1, and various modified embodiments which do not depart from the fundamental scope are possible, such as embodiments using various different type of component mounter.

SYMBOL DESCRIPTIONS



[0060] 11: Base, 12: Mounting module (component mounter), 14: Feeder, 15: Circuit board conveyance device, 16: Camera, 17: Component mounting device, 21: Suction nozzle, 22: Mounting head, 23: X-axis slide mechanism; 24: Y-axis slide mechanism, 31: Y-axis motor, 33: Y-axis slide, 54: Motor for rotating head, 55: Nozzle holder, 52: Nozzle raising and lowering motor, 53: Nozzle raising and lowering mechanism, 62: Lens, 64: Light source, 65: Light emitting element, A to D: Components


Claims

1. What is claimed is a component mounter which is equipped with a camera to take images of components being held on suction nozzles illuminated by a light source from below and an image processing means to process the image signal of said camera in order to recognize the pickup position of the components; and which mounts said components on a circuit board considering the deviation of the pickup position of said components with respect to said suction nozzles based on the recognition results of the said image processing means;
characterized in that the component mounter is equipped with a recognized position deviation correction means for correcting the deviation in the recognized position of said components due to the positional relationship between the component and the light source which considers the deviation in the recognized position of said components of which an image is taken by said camera caused by the changing light and dark condition of the component (due to the light source) from said light source due to the positional relationship between the light source and
said components being held by the suction nozzles.
 
2. The component mounter according to claim 1 characterized in that it is equipped with multiple suction nozzles and takes a single image of all the components gathered within the field of view of said camera, with said multiple suction nozzles holding each of one of multiple components.
 
3. The component mounter according to claim 1 or claim 2 characterized in that it is equipped with a recognized position deviation amount measuring means for measuring the deviation amount of the recognized position of the components being held on the said suction nozzles and a memorizing means for memorizing the data of the recognized position deviation amount measured by the said recognized position deviation amount measuring means,
wherein the said recognized position deviation correction means corrects the deviation in the recognized position of the components being held by said suction nozzles by reading the data of the recognized position deviation amount from the said memorizing means during production.
 
4. The component mounter according to claim 3 characterized in that it is configured such that the center of the field of view of said camera is aligned with the center of said light source,
and that said recognized position deviation amount measurement means, as well as recognizing the position of components using said image processing means by taking an image of the components while they are being held on said suction nozzles with the center of said suction nozzles being aligned with the center of the field of view of said camera before starting production, calculates said recognized position deviation amount as the difference between the movement distance of said nozzle and the distance separating the two recognized positions of the component, which are recognized using the image processing means by moving the suction nozzle to the position for taking images during production and taking an image of the component using the camera.
 
5. The component mounter according to claim 1 or claim 2 characterized in that it is equipped with a memorizing means for memorizing tables containing said recognized position deviation amounts as parameters which represent the positional relationship between a component being held on a suction nozzle and said light source,
wherein the said recognized position deviation correction means corrects the deviation in the recognized position of the components being held by said suction nozzles by reading the data of the recognized position deviation amount which is based on the positional relationship of said light source said component being held on a suction nozzle from the said table which is memorized in said memorizing means during production.
 
6. The component mounter according to claim 5 characterized in that, in said memorizing means, a said table is memorized for each component type,
and said recognized position deviation correction means corrects the deviation in the recognized position of said components being held by suction nozzles by reading the data of said recognized position deviation amounts which are based on the positional relationship of said light source and said component being held on a suction nozzle from a table selected based on the component type at that time which is among the tables for each component type memorized in the memorizing means during production.
 




Drawing











































Search report










Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description