JP7630101B2 - Parts Imaging Device - Google Patents

Description

The present invention relates to an imaging device for imaging parts.

The component mounting device uses a nozzle on a mounting head that moves horizontally to pick up components supplied by a component supply unit and mounts them on a board held by a board transport conveyor. Some such component mounting devices are known to be equipped with a component recognition camera (component imaging device) that captures the position of the component held by the nozzle to improve component mounting accuracy, and a board recognition camera that moves together with the mounting head to capture an image of a mark formed on the board (for example, Patent Document 1).

In Patent Document 1, in order to ensure component mounting accuracy by correcting the positional relationship between the nozzle of a detachable mounting head and the board recognition camera, a glass plate with a reference mark formed thereon is placed on the top surface of the component recognition camera so that the reference mark is within the field of view of the component recognition camera, and the mounting head is moved so that the nozzle is within this field of view. In this state, the positions of the nozzle and the reference mark are detected by the component recognition camera, and the positional relationship between the nozzle and the board recognition camera is calculated from the reference mark imaged by the board recognition camera and the position of the optical axis of the board recognition camera.

JP 2004-179636 A

The component recognition camera detects the position of the component held by the nozzle from the position of the camera's optical axis. However, during the continuous production of mounting boards, the camera's optical axis may become misaligned (distorted) due to changes over time caused by heat generation in the imaging element of the component recognition camera, and in order to maintain component mounting accuracy, it is necessary to periodically detect and appropriately correct the misalignment of the optical axis of the component recognition camera. However, conventional technologies including Patent Document 1 do not disclose a method for detecting the misalignment of the optical axis of the component recognition camera during the production of mounting boards, and there is room for further improvement in order to improve component mounting accuracy.

The present invention aims to provide a component imaging device that can correct the misalignment of the optical axis of a camera that images a component.

The component imaging device of the present invention comprises a plurality of cameras whose imaging fields of view are arranged in series and which image a component, a transparent plate arranged between the plurality of cameras and the component, a mark on the transparent plate within the imaging fields of view of the plurality of cameras but outside the imaging range when the plurality of cameras image the component, and a positional deviation calculation unit that calculates a positional deviation amount of the imaging fields of view of the plurality of cameras based on the imaging results of the plurality of cameras each capturing an image of the mark.

The present invention makes it possible to correct misalignment of the optical axis of a camera that captures an image of a part.

FIG. 1 is a plan view of a component mounting apparatus according to an embodiment of the present invention; FIG. 1 is a configuration explanatory diagram of a component mounting device according to an embodiment of the present invention; FIG. 1 is a perspective view showing the inside of a component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; 1A is a perspective view showing a main part of a first camera unit of a component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; FIG. 1B is a perspective view showing a main part of a second camera unit of the component recognition camera; FIG. 1 is a perspective view showing a main part of a component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; 1A is a plan view, FIG. 1B is a front view, and FIG. 1C is a side view showing a main part of a component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention. FIG. 2A is an explanatory diagram of an optical system of a first camera unit of a component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; FIG. 2B is an explanatory diagram of an optical system of a second camera unit of the component recognition camera; FIG. 13 is an explanatory diagram of another example of the optical system of the first camera unit of the component recognition camera provided in the component mounting device according to the embodiment of the present invention; 1A and 1B are explanatory diagrams illustrating an imaging field of a component recognition camera provided in a component mounting device according to an embodiment of the present invention; 1A and 1B are explanatory diagrams of an imaging field of a second component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; FIG. 1 is a block diagram showing a configuration of a control system of a component mounting apparatus according to an embodiment of the present invention. 1A and 1B are explanatory diagrams illustrating an image of a component held by a nozzle by a component recognition camera provided in a component mounting device according to an embodiment of the present invention; 1A and 1B are explanatory diagrams illustrating an image of a component held by a nozzle by a second component recognition camera provided in a component mounting apparatus according to an embodiment of the present invention; 1A and 1B are diagrams showing examples of images of marks captured by a second component recognition camera included in a component mounting device according to an embodiment of the present invention; FIG. 13 is a diagram showing an example of a combined image of components held by a nozzle captured by a second component recognition camera provided in the component mounting apparatus according to the embodiment of the present invention; FIG. 13 is a perspective view showing a main part of a component recognition camera having another optical axis bending unit provided in the component mounting apparatus according to the embodiment of the present invention; 1A is a plan view, FIG. 1B is a front view, and FIG. 1C is a side view showing a main part of a component recognition camera having another optical axis bending unit provided in a component mounting device according to an embodiment of the present invention. FIG. 13 is a perspective view showing a main part of a third component recognition camera provided in the component mounting apparatus according to the embodiment of the present invention; FIG. 1A is an explanatory diagram of an imaging field of a third component recognition camera provided in a component mounting device according to an embodiment of the present invention; FIG. 1C is an explanatory diagram of an imaging of a component held by a nozzle by the third component recognition camera;

An embodiment of the present invention will be described in detail below with reference to the drawings. The configurations, shapes, etc. described below are examples for explanatory purposes and can be modified as appropriate depending on the specifications of the component mounting device and component recognition camera. In the following, the same reference numerals are used for corresponding elements in all drawings, and duplicated explanations will be omitted. In FIG. 1 and in some parts described below, the X-axis in the board transport direction (left-right direction in FIG. 1) and the Y-axis orthogonal to the board transport direction (up-down direction in FIG. 1) are shown as two axes that are orthogonal to each other in the horizontal plane. In FIG. 2 and in some parts described below, the Z-axis (up-down direction in FIG. 2) is shown as the height direction that is orthogonal to the horizontal plane.

First, the configuration of the component mounting device 1 will be described with reference to Figures 1 and 2. Note that Figure 2 shows a schematic view of a portion of the component mounting device 1 in Figure 1. The component mounting device 1 has the function of performing component mounting work, which involves attaching components supplied from a component supply unit to a board. A board transport mechanism 2 is disposed along the X-axis in the center of the base 1a. The board transport mechanism 2 transports the board 3 transported from the upstream side to the mounting work position, positions it, and holds it. In addition, the board transport mechanism 2 transports the board 3 downstream after the component mounting work has been completed.

Component supply units 4 are arranged on both sides of the board transport mechanism 2 (front and rear directions of the Y axis). Each component supply unit 4 has multiple tape feeders 5 attached in parallel along the X axis. The tape feeders 5 feed a component tape, on which pockets for storing components D are formed, at a pitch rate in a direction (tape feed direction) from the outside of the component supply unit 4 toward the board transport mechanism 2, thereby supplying components D to a component supply position 5a from which the components D are picked up by a mounting head, which will be described below.

In Figures 1 and 2, a Y-axis table 6 equipped with a linear drive mechanism is arranged along the Y-axis at both ends of the X-axis on the top surface of the base 1a. A beam 7 similarly equipped with a linear drive mechanism is connected to the Y-axis table 6 so that it can move freely along the Y-axis. The beam 7 is arranged along the X-axis. A mounting head 8 is attached to the beam 7 so that it can move freely along the X-axis. The mounting head 8 is equipped with a suction unit 8a that can lift and lower while suctioning and holding a component D. A nozzle 8b that suctions and holds the component D is attached to the lower end of each suction unit 8a.

In FIG. 1, the Y-axis table 6 and the beam 7 constitute a head movement mechanism 9 that moves the mounting head 8 along the X-axis and Y-axis. The head movement mechanism 9 and the mounting head 8 perform a mounting turn in which the nozzle 8b picks up and removes the component D from the component supply position 5a of the tape feeder 5 arranged in the component supply section 4, and mounts it at the mounting position of the board 3 positioned by the board transport mechanism 2. In other words, the Y-axis table 6, the beam 7 and the mounting head 8 constitute a component mounting means that holds the component D supplied to the component supply position 5a of the tape feeder 5 with the nozzle 8b and mounts it on the board 3.

In Figures 1 and 2, a component recognition camera 20 is disposed between the component supply unit 4 and the board transport mechanism 2. When the mounting head 8, which has picked up a component D from the component supply unit 4, moves above the component recognition camera 20, the component recognition camera 20 captures an image of the component D held by the mounting head 8 to recognize the holding posture of the component D. A board recognition camera 10 is attached to the plate 7a to which the mounting head 8 is attached. The board recognition camera 10 moves integrally with the mounting head 8.

As the mounting head 8 moves, the board recognition camera 10 moves above the board 3 positioned by the board transport mechanism 2, and captures an image of the board mark 3a provided on the board 3 to recognize the position of the board 3. When the mounting head 8 mounts components on the board 3, the mounting position is corrected taking into account the recognition results of the component D by the component recognition camera 20 and the recognition results of the board position by the board recognition camera 10.

In FIG. 2, a cart 11 with multiple tape feeders 5 already attached to a feeder base 11a is set in the component supply unit 4. The cart 11 holds a tape reel 13 that stores a component tape 12 holding components D in a wound state. The component tape 12 pulled out from the tape reel 13 is pitch-fed by the tape feeder 5 to the component supply position 5a.

In FIG. 1, a touch panel 14 operated by the worker is installed at the position where the worker works on the front side of the component mounting device 1. The touch panel 14 displays various information on its display, and the worker inputs data and operates the component mounting device 1 using operation buttons displayed on the display.

Next, referring to FIG. 3, an overview of the configuration of the part recognition camera 20 will be described. FIG. 3 shows a schematic view of the inside of the part recognition camera 20 seen through the housing 21 of the part recognition camera 20. The part recognition camera 20 is provided with a plurality of first camera units 22 (four in this case) arranged in a straight line along the X-axis. The plurality of first camera units 22 constitute a first camera group G1. The part recognition camera 20 is also provided with a plurality of second camera units 23 (four in this case) arranged in a straight line along the X-axis. The plurality of second camera units 23 constitute a second camera group G2.

The first camera group G1 and the second camera group G2 are arranged adjacent to each other along the Y axis. The first camera unit 22 of the first camera group G1 and the second camera unit 23 of the second camera group G2 are arranged so that their positions in the X axis direction are staggered (staggered arrangement). That is, the second camera unit 23 is arranged so that its center is located at the boundary position between two adjacent first camera units 22 in the X axis direction. Similarly, the first camera unit 22 is arranged so that its center is located at the boundary position between two adjacent second camera units 23. A transparent plate 24 on which a number of marks 25 are formed is arranged above a predetermined position where parts of the first camera unit 22 and the second camera unit 23 are arranged alternately.

Next, the details of the configuration of the part recognition camera 20 will be described with reference to Figures 4 to 7. For convenience, Figures 5 to 7 omit the illustration of the housing 22a of the first camera unit 22 and the housing 23a of the second camera unit 23 to clearly show the positional relationship of the internal components of the part recognition camera 20.

6(b) and 6(c), the transparent plate 24 is disposed on the opening 21b formed by cutting out the upper portion 21a of the housing 21 of the part recognition camera 20. The transparent plate 24 is formed of a plate-like glass that transmits light. In FIG. 6(a), a part imaging field of view 24a is set in the center of the transparent plate 24 in the Y-axis direction, through which the optical axes of the cameras pass when the first camera unit 22 and the second camera unit 23 image the part D held by the nozzle 8b. On the transparent plate 24, a plurality of marks 25 are arranged in series along the X-axis, and are arranged in two rows in the Y-axis direction, sandwiching the part imaging field of view 24a. In other words, the plurality of marks 25 are disposed in positions that do not interfere with the imaging of the part D by the first camera unit 22 and the second camera unit 23.

Next, the optical system of the first camera unit 22 will be described with reference to Fig. 4(a) and Fig. 7(a). Fig. 4(a) shows a schematic diagram of the inside of the first camera unit 22 seen through the housing 22a of the first camera unit 22. For convenience, Fig. 7(a) shows only the configuration related to the first camera unit 22 inside the component recognition camera 20. The first camera unit 22 has a first imaging section 22b having an imaging element such as a two-dimensional CMOS sensor inside the housing 22a, and a first lens 22c located between the component D to be imaged and the first imaging section 22b.

The first camera unit 22 is installed with its optical axis 22d facing upward, and captures the target part D from below. The first illumination unit 26 is installed above the first lens 22c in a position that does not interfere with the imaging by the first camera unit 22. The first illumination unit 26 is configured with multiple LED chips, etc., and emits light 26a from below, which illuminates the target part (such as part D) or the mark 25 on the transparent plate 24.

Next, the optical system of the second camera unit 23 will be described with reference to Fig. 4(b) and Fig. 7(b). Fig. 4(b) shows a schematic diagram of the inside of the second camera unit 23 seen through the housing 23a of the second camera unit 23. For convenience, Fig. 7(b) shows only the configuration related to the second camera unit 23 inside the component recognition camera 20. The second camera unit 23 has a second imaging section 23b having an imaging element such as a two-dimensional CMOS sensor inside the housing 23a, and a second lens 23c located between the component D to be imaged and the second imaging section 23b.

The second camera unit 23 is installed with its optical axis 23d facing upward. In the second camera unit 23, a first mirror 27 is disposed below the transparent plate 24. A second mirror 28 is disposed above the second lens 23c, at a position along the Y axis from the first mirror 27. The optical axis 23d of the second camera unit 23 is refracted by the second mirror 28 toward the first mirror 27. Furthermore, the optical axis 23d is refracted upward by the first mirror 27.

In this way, the optical axis 23d is refracted by the second mirror 28 and the first mirror 27, and the second camera unit 23 captures the image of the target part D from below. That is, the first mirror 27 and the second mirror 28 (mirrors) form an optical axis refraction section R that guides the image of the part D held in the nozzle 8b to the second camera unit 23 (camera of the second camera group). In the part recognition camera 20, the first mirror 27 and the second mirror 28 are arranged for each camera (second camera unit 23) of the second camera group G2 (see Figures 5 and 6).

In FIG. 7(b), a second illumination unit 29 is installed above the second lens 23c at a position that does not interfere with imaging by the second camera unit 23. The second illumination unit 29 is configured with a plurality of LED chips, etc., and emits light 29a that illuminates the imaging target (such as component D) or the mark 25 on the transparent plate 24. The light 29a emitted from the second illumination unit 29 is refracted by the second mirror 28 and the first mirror 27, thereby illuminating the imaging target (such as component D) or the mark 25 on the transparent plate 24 from below.

In Figures 7(a) and 7(b), when the part recognition camera 20 (part imaging device) images the part D held by the nozzle 8b, the nozzle 8b holding the part D is moved along the Y axis (arrow a) while the first lighting unit 26 and the second lighting unit 29 are irradiating the part with light 26a and 29a. The first camera unit 22 and the second camera unit 23 image (scan image) the part D from below as the part D passes above the part imaging field of view 24a of the transparent plate 24.

Now, referring to FIG. 8, another embodiment of the optical system of the first camera unit 22 will be described. This embodiment of the optical system of the first camera unit 22 differs from the optical system of the first camera unit 22 described above in that a half mirror 30 is disposed above the first lens 22c. The optical axis 22d of the first camera unit 22 passes through the half mirror 30, and the first camera unit 22 captures an image of the target part D from below.

The third illumination unit 31 is installed at a position along the Y axis from the half mirror 30. The third illumination unit 31 is configured with a plurality of LED chips and the like, and emits light 31a sideways to illuminate the imaging object (such as part D) or the mark 25 on the transparent plate 24. The light 31a emitted from the third illumination unit 31 is refracted upward by the half mirror 30, thereby illuminating the imaging object (such as part D) or the mark 25 on the transparent plate 24 from below. In this way, the part recognition camera 20 is provided with illumination units (first illumination unit 26, second illumination unit 29, third illumination unit 31) that are arranged for each of the plurality of cameras (first camera unit 22, second camera unit 23) and illuminate the part D held by the nozzle 8b and the mark 25 on the transparent plate 24.

Next, the imaging field of view of the part recognition camera 20 will be described with reference to FIG. 9. In FIG. 9, the four first camera units 22 in the first camera group G1 are referred to as first camera unit 22A to first camera unit 22D, starting from the left in the X-axis direction. Additionally, the four second camera units 23 in the second camera group G2 are referred to as first camera unit 23A to first camera unit 23D, starting from the left in the X-axis direction.

In Figures 9(a) and 9(b), the center of the second camera unit 23A in the X-axis direction is located at the boundary between the first camera unit 22A and the first camera unit 22B, which are adjacent in the X-axis direction. Also, the center of the first camera unit 23B in the X-axis direction is located at the boundary between the second camera unit 23A and the second camera unit 23B, which are adjacent in the X-axis direction. Similarly, the first camera units 22A to 22D and the second camera units 23A to 23D are installed.

As a result, on the transparent plate 24 including the component imaging field 24a (hatched with dots in FIG. 9B), the imaging fields A1, A3, A5, A7 of the first camera units 22A to 22D and the imaging fields A2, A4, A6, A8 of the second camera units 23A to 23D are alternately arranged, such as the imaging field A1 of the first camera unit 22A, the imaging field A2 of the second camera unit 23A, the imaging field A3 of the first camera unit 22B, and the imaging field A4 of the second camera unit 23B from the left in the X-axis direction.

In FIG. 9(b), the width LX1 in the X-axis direction and the width LY1 in the Y-axis direction of the imaging fields A1, A3, A5, and A7 of the first camera units 22A to 22D are the same as the width LX2 in the X-axis direction and the width LY2 in the Y-axis direction of the imaging fields A2, A4, A6, and A8 of the second camera units 23A to 23D. In addition, in the X-axis direction, the imaging field A2 of the second camera unit 23A is in contact with the imaging field A1 of the first camera unit 22A and the imaging field A3 of the first camera unit 22B, which are adjacent to the left and right. In other words, the imaging fields A1, A3, A5, and A7 of the first camera units 22A to 22D and the imaging fields A2, A4, A6, and A8 of the second camera units 23A to 23D are arranged so that they are alternately in contact with each other in one direction (the X-axis direction).

The first lens 22c and the first imaging section 22b of the first camera units 22A-22D and the second lens 23c and the second imaging section 23b of the second camera units 23A-23D are telecentric optical systems in which the chief ray is parallel to the optical axes 22d, 23d. In other words, the multiple cameras of the first camera group G1 (first camera units 22A-22D) and the multiple cameras of the second camera group G2 (second camera units 23A-23D) have telecentric optical systems.

Alternatively, the multiple cameras (first camera units 22A-22D, second camera units 23A-23D) are optical systems in which the chief ray and the optical axes 22d, 23d are nearly parallel and the angle of view is small (narrow). In this way, the component recognition camera 20 realizes a component imaging field of view 24a that is long in one direction without using a lens with a large diameter by arranging the cameras (first camera units 22A-22D, second camera units 23A-23D) with an optical system having a small angle of view so that the imaging fields of view A1-A8 are alternately arranged in one direction (X-axis direction).

As described above, the part recognition camera 20 is a part imaging device that includes a first camera group G1 consisting of a plurality of cameras (first camera units 22A to 22D) arranged in series in one direction (X-axis direction) and imaging part D, a second camera group G2 consisting of a plurality of cameras (second camera units 23A to 23D) arranged in series in one direction parallel to the first camera group G1 and imaging part D, and an optical axis refraction section R that arranges the imaging fields A1, A3, A5, and A7 of the cameras of the first camera group G1 and the imaging fields A2, A4, A6, and A8 of the cameras of the second camera group in series. In addition, the part recognition camera 20 is arranged such that the cameras of the first camera group G1 and the cameras of the second camera group G2 are arranged so that the imaging fields A1 to A8 are arranged alternately.

Next, the second component recognition camera 32 (hereinafter simply referred to as "component recognition camera 32") will be described with reference to FIG. 10. The component recognition camera 32 includes four first camera units 33A-33D arranged in the X-axis direction and each having a first lens 33b and a first imaging section 33a, and four second camera units 34A-34D arranged in the X-axis direction and each having a second lens 34b and a second imaging section 34a. The angle of view of the first camera units 33A-33D and second camera units 34A-34D of the component recognition camera 32 is larger (wider) than in the example of FIG. 9, which is different from the component recognition camera 20. Hereinafter, the same components as those of the component recognition camera 20 are denoted by the same reference numerals, and detailed description will be omitted.

In Figures 10(a) and 10(b), the width LX3 in the X-axis direction of the imaging fields B1, B3, B5, and B7 of the first camera units 33A to 33D and the width LX4 in the X-axis direction of the imaging fields B2, B4, B6, and B8 of the second camera units 34A to 34D are greater than the widths LX1 and LX2 in the X-axis direction of the imaging fields A1 to A8 in Figure 9(b). As a result, in the component recognition camera 32, adjacent imaging fields B1 to B8 of the first camera units 33A to 33D and the second camera units 34A to 34D partially overlap each other in one direction (X-axis direction).

The component recognition camera 32 has imaging fields of view B1 to B8 that partially overlap each other, so that even if the optical axes 33c, 34c of the first camera units 33A to 33D or the second camera units 34A to 34D are misaligned due to heat generation or manufacturing of the component recognition camera 32 as described below, it is possible to prevent gaps from occurring between adjacent imaging fields of view B1 to B8 (component imaging fields of view 24a that are long in one direction).

Next, referring to FIG. 11, the configuration of the control system of the component mounting device 1 equipped with the component recognition camera 20 (component imaging device) will be described. The configuration of the control system of the component mounting device 1 equipped with the second component recognition camera 32 (component imaging device) is similar, and detailed description will be omitted. The component mounting device 1 is equipped with a control unit 40, a board conveying mechanism 2, a tape feeder 5, a mounting head 8, a head moving mechanism 9, a component recognition camera 20, a board recognition camera 10, and a touch panel 14. The control unit 40 is equipped with a mounting operation processing unit 41, a component imaging processing unit 42, an image processing unit 43, a pickup component position calculation unit 44, a mark imaging processing unit 45, a position deviation amount calculation unit 46, and a mounting memory unit 47. The mounting memory unit 47 is a storage device, and stores mounting data 48, component imaging results 49, mounting correction values 50, mark imaging results 51, imaging field position deviation amount 52, etc.

The mounting data 48 stores information necessary for component mounting work, such as the size of the board 3, the type and mounting position (XY coordinates) of the component D to be mounted, and the type of mounting head 8, for each type of board 3 (board type). The mounting operation processing unit 41 controls each part of the component mounting device 1 based on the mounting data 48, holds the component D supplied by the tape feeder 5 with the nozzle 8b of the mounting head 8, corrects the position (X-axis direction, Y-axis direction) of the nozzle 8b based on a mounting correction value 50 described later, and controls the component mounting work to mount the component D at the mounting position on the board 3 held at the mounting work position.

In FIG. 11, the component imaging processing unit 42 controls the head moving mechanism 9 and the component recognition camera 20 during the component mounting operation to image (scan) the component D held by the nozzle 8b while moving the mounting head 8 holding the component D on the nozzle 8b above the component recognition camera 20. At that time, the component imaging processing unit 42 images the component D with the first camera unit 22 and the second camera unit 23 while illuminating the component D with the first illumination unit 26 and the second illumination unit 29. The imaging result of the component D is processed by the image processing unit 43 and then stored in the mounting storage unit 47 as the component imaging result 49. The pickup component position calculation unit 44 calculates the position of the center of the component D as seen from the center (pickup position) of the nozzle 8b based on the stored component imaging result 49, and stores it in the mounting storage unit 47 as the mounting correction value 50.

Now, referring to Figs. 12 and 13, the imaging of component D by the component recognition camera 20 or component recognition camera 32 (component imaging device) shown in Fig. 9 will be described in detail. Fig. 12 shows an example of imaging by the component recognition camera 20 having the imaging fields A1 to A8 shown in Fig. 9, and Fig. 13 shows an example of imaging by the component recognition camera 32 having the imaging fields B1 to B8 shown in Fig. 10. Fig. 12 shows an example of using a mounting head 8 having 16 nozzles 8b that hold small components D1 (hereinafter referred to as a "16-nozzle mounting head"). The 16-nozzle mounting head has two rows of eight nozzles 8b arranged in series along the X-axis, front to back in the Y-axis direction. The pitch (spacing) of the nozzles 8b arranged along the X-axis is designed to be the same as the pitch in the X-axis direction of the centers (optical axes 22d, 23d) of the imaging fields A1 to A8 of the component recognition camera 20.

In FIG. 12(b), the component imaging processing unit 42 first moves the 16-nozzle mounting head to a position where the center of the nozzle 8b at the left end in the X-axis direction passes through the center of the imaging field A1. Next, the component imaging processing unit 42 scans and images the component D1 held by each of the eight nozzles 8b on the front side while moving the 16-nozzle mounting head along the Y-axis (arrow b). Next, the component imaging processing unit 42 scans and images the component D1 held by each of the eight nozzles 8b on the rear side while moving the 16-nozzle mounting head along the Y-axis (arrow b). The image processing unit 43 corrects the imaging results of the component D1 by each camera based on the imaging field position deviation amount 52 described later, and stores the result as the component imaging result 49 in the mounting storage unit 47.

In this example, multiple cameras (first camera units 22A-22D, second camera units 23A-23D) are positioned corresponding to the position of the component D1 to be imaged, so that the components D1 held by multiple nozzles 8b can be imaged at once in the imaging fields A1-A8 of each camera. For example, the component D1 held by the nozzle 8b at the left end in the X-axis direction of the 16-nozzle mounting head is imaged by the first camera unit 22A as it passes through the imaging field A1. Since the distortion of the lenses (first lens 22c, second lens 23c) is small near the center of the imaging fields A1-A8, the area around the nozzle 8b of the component D1 held by the nozzle 8b can be imaged (recognized) more accurately.

Figure 13 shows an example of using a mounting head 8 having four nozzles 8b that hold a large component D2 (hereinafter referred to as a "four-nozzle mounting head"). The four-nozzle mounting head has four nozzles 8b that are arranged in series along the X-axis. The pitch (spacing) of the nozzles 8b arranged along the X-axis is designed to be twice the pitch in the X-axis direction of the centers (optical axes 33c, 34c) of the imaging fields B1 to B8 of the component recognition camera 32.

In FIG. 13(b), the component imaging processing unit 42 first moves the center of the nozzle 8b at the left end in the X-axis direction of the four-nozzle mounting head to a position where it passes through the midpoint between the center of the imaging field of view B1 and the center of the imaging field of view B2. Next, the component imaging processing unit 42 scans and images the component D2 held by each of the four nozzles 8b while moving the four-nozzle mounting head along the Y-axis (arrow c). The image processing unit 43 corrects the imaging results of the component D2 taken by each camera based on the imaging field of view position deviation amount 52, and further combines and stores the result in the mounting memory unit 47 as the component imaging result 49.

In this example, component D2 held by nozzle 8b at the left end in the X-axis direction of the four-nozzle mounting head is imaged by first camera unit 33A and second camera unit 34A as it passes through imaging field of view B1 and imaging field of view B2. That is, the component recognition camera 32 images one component D2 with a camera of the first camera group G1 (first camera unit 33A) and a camera of the second camera group G2 (second camera unit 34A). The imaging results by the first camera unit 33A and the second camera unit 34A are corrected by the image processing unit 43 based on the imaging field position deviation amount 52, and then combined into one image that shows component D2, and stored as component imaging result 49 (see FIG. 15).

In this way, the part recognition camera 32 (part imaging device) can simultaneously image the part D2 held by multiple nozzles 8b. Furthermore, when imaging a part larger than part D2, the part is recognized based on the image of the camera in the imaging field of view through which the part passes. For example, for a part large enough to pass across imaging fields B1 to B4, the four imaging results captured by the two first camera units 33A, 33B of the first camera group G1 and the two second camera units 34A, 34B of the second camera group G2 are image processed (corrected and combined) to create an image of a single part.

In FIG. 11, when correcting the imaging field of view, the mark imaging processing unit 45 uses the first illumination unit 26 and the second illumination unit 29 to illuminate the mark 25 provided outside the component imaging field of view 24a of one transparent plate 24, while causing the first camera unit 22 and the second camera unit 23 to capture an image (still image) of the mark 25. The mark imaging processing unit 45 also stores the imaging results of the mark 25 as mark imaging results 51 for each of the multiple cameras (first camera units 22A-22D, second camera units 23A-23D) in the mounting storage unit 47. The positional deviation amount calculation unit 46 calculates the positional deviation amount from the ideal state of the imaging fields of view of the multiple cameras based on the stored mark imaging results 51. The calculated positional deviation amount is stored in the mounting storage unit 47 as the imaging field of view positional deviation amount 52.

Now, referring to FIG. 14, the imaging of the mark 25 by the component recognition camera 32 when correcting the imaging field of view will be described. The method of correcting the imaging field of view using the mark 25 by the component recognition camera 20 is similar to that of the component recognition camera 32, and so a description thereof will be omitted. In the process of repeatedly capturing images of the component held by the nozzle 8b during component mounting work, the first camera units 33A-33D and second camera units 34A-34D of the component recognition camera 32 may experience distortion over time in the housing of the component recognition camera 32 and the housings of each unit due to heat generated by the imaging element and the illumination units (first illumination unit 26, second illumination unit 29).

The marks 25 are provided within the imaging fields B1-B8 of the multiple cameras (first camera units 33A-33D, second camera units 34A-34D) on one transparent plate 24, but outside the imaging range (component imaging field 24a) when the multiple cameras image the component, in order to obtain the imaging field position shift amount 52 for canceling out the distortion of the first camera units 33A-33D and the second camera units 34A-34D. The transparent plate 24 is disposed between the multiple cameras and the component held by the nozzle 8b to be imaged.

Figure 14(a) shows an image 60 obtained by the mark imaging processing unit 45 causing the first camera unit 33A to capture a still image of the mark 25 in the part recognition camera 32 having the imaging fields of view B1 to B8 shown in Figure 9. That is, the captured image 60 is an image within the imaging field of view B1 of the first camera unit 33A. Figure 14(b) shows an image 61 obtained by the mark imaging processing unit 45 causing the second camera unit 34A to capture a still image of the mark 25. That is, the captured image 61 is an image within the imaging field of view B2 of the second camera unit 34A.

In this example, the multiple cameras (first camera units 33A-33D, second camera units 34A-34D) are positioned so that within the imaging fields B1-B8 of the multiple cameras, four marks 25 are captured by the component recognition camera 32 without distortion. That is, at least two marks 25 are provided on the transparent plate 24 in each of the imaging fields B1-B8 of the multiple cameras. In Figures 14(a) and 14(b), the four dotted circles indicate the positions of the marks 25 in an ideal state. The four solid circles (or parts of the circles) indicate the marks 25 captured by the first camera unit 33A and the second camera unit 34A. The optical axes 33c and 34c are misaligned due to distortion, so the positions of the captured marks 25 are shifted from the ideal state.

In FIG. 14(a), the four marks 25 captured in the imaging field of view B1 are referred to as marks 25A to 25D in order, moving clockwise from the top left. The center 60c of the captured image 60 is the center of the imaging field of view B1 of the first camera unit 33A. In FIG. 14(b), the four marks 25 captured in the imaging field of view B1 are referred to as marks 25E to 25H in order, moving clockwise from the top left. The center 61c of the captured image 61 is the center of the imaging field of view B2 of the second camera unit 34A.

Now, referring to FIG. 14(a), the imaging field of view positional deviation calculation process performed by the positional deviation calculation unit 46 to calculate the amount of positional deviation in the imaging field of view B1 of the first camera unit 33A based on the captured image 60 (imaging result) of the marks 25A to 25D captured by the first camera unit 33A will be described. In the imaging field of view positional deviation calculation process, the positional deviation calculation unit 46 first processes the captured image 60 to extract the center positions of the marks 25A to 25D. In this example, the mark 25B is partially outside the imaging field of view B1, so the center position cannot be extracted.

The positional deviation calculation unit 46 selects two marks, 25A and 25D, from the three marks 25A, 25C, and 25D whose center positions have been extracted. The positional deviation calculation unit 46 then calculates the center position (XA, YA) of the selected mark 25A and the center position (XD, YD) of the mark 25D, with the center 60c of the captured image 60 (the center of the imaging field of view B1) as the origin.

14(a), the positional deviation calculation unit 46 then calculates the positional deviation (ΔXK1, ΔYK1) of the position of the center K1 of the four marks 25A to 25D from the center 60c (center of the imaging field of view B1) of the captured image 60 and the deviation ΔθK1 in the θ direction with the Z axis as the rotation axis from the calculated center position (XA, YA) of the mark 25A, the center position (XD, YD) of the mark 25D, and the center position (XA0, YA0) of the mark 25A in the ideal state and the center position (XD0, YD0) of the mark 25D. The positional deviation calculation unit 46 stores the calculated positional deviation (ΔXK1, ΔYK1) of the center K1 and the deviation ΔθK1 in the θ direction as the imaging field of view positional deviation 52 in the implementation storage unit 47. Note that the center K1 of the four marks 25A to 25D in the ideal state coincides with the center 60c (center of the imaging field of view B1) of the captured image 60.

In FIG. 14B, in the case of the second camera unit 34A, the positional deviation amount calculation unit 46 selects two marks, 25E and 25F, from the four marks 25E to 25H whose center positions have been extracted, and calculates the positional deviation amount (ΔXK2, ΔYK2) of the position of the center of gravity K2 of the four marks 25E to 25H and the deviation amount in the θ direction ΔθK2. In this way, the positional deviation amount calculation unit 46 calculates the imaging field positional deviation amount 52 (the positional deviation amount of the imaging field of one camera) from the center positions of at least two marks 25E, 25F that appear in the imaging field of view B2 of the second camera unit 34A (one of the multiple cameras). By using the center positions of the two marks 25E, 25F, in addition to the positional deviation amount (ΔXK2, ΔYK2) of the center of gravity K2, the deviation amount in the θ direction ΔθK2 can also be calculated.

The mark imaging processing unit 45 captures still images of the marks 25 using the multiple cameras (first camera units 33A-33D, second camera units 34A-34D) of the component recognition camera 32, and the positional deviation calculation unit 46 calculates the image viewing field positional deviation amount 52, i.e., corrects the image viewing fields B1-B8, during idle time during component mounting work. For example, these are performed during idle time when the mounting head 8 is not above the component recognition camera 32, such as while the mounting head 8 is removing the component D from the tape feeder 5 or mounting the component D on the board 3.

That is, during free time, the mark imaging processing unit 45 images the mark 25, and the position deviation amount calculation unit 46 calculates the latest imaging field position deviation amount 52, and the data in the mounting memory unit 47 is updated. This allows the deviation (imaging field position deviation amount 52) of the optical axes 33c, 34c of the cameras (multiple cameras of the component recognition camera 32) that image the component D to be corrected without reducing the efficiency of the component mounting work, and the component D can be mounted in the mounting position with high precision. Note that when imaging the component D held by the nozzle 8b, the mark 25 may also be imaged at the same time to calculate the position deviation amount of the imaging fields B1 to B8.

Next, referring to FIG. 15, the image processing of the imaging results by the image processing unit 43 will be described. FIG. 15 shows a combined image 62 obtained by the image processing unit 43 processing the imaging results of the first camera unit 33A and the second camera unit 34A imaging the component D2 held by the nozzle 8b at the left end in the X-axis direction of the four-nozzle mounting head shown in FIG. 13. Here, the positions of the center of the nozzle 8b and the center of the component D2 are the same, that is, the positional deviation of the suction position of the component D2 relative to the nozzle 8b is zero. Also, the optical axes 33c, 34c of the first camera unit 33A and the second camera unit 34A are offset by the imaging field positional deviation amount 52, as shown in FIG. 14(a) and FIG. 14(b).

In FIG. 15, the left side of the combined image 62 is the result of the image processing unit 43 correcting the image obtained by scanning and imaging the part D2 by the first camera unit 33A when the part D2 passes through the imaging field of view B1 based on the imaging field position deviation amount 52 (ΔXK1, ΔYK1, ΔθK1) after the scanning and imaging result is obtained by the first camera unit 33A when the part D2 passes through the imaging field of view B2 based on the imaging field position deviation amount 52 (ΔXK2, ΔYK2, ΔθK2).

The dotted figure 63 on the left side of the combined image 62 shows an image of the part D2 when the image captured by the first camera unit 33A is not corrected by the image viewing field position shift amount 52. The dotted figure 64 on the right side of the combined image 62 shows an image of the part D2 when the image captured by the second camera unit 34A is not corrected by the image viewing field position shift amount 52. By combining the images after the image processing unit 43 corrects the shift of the optical axes 33c and 34c based on the image viewing field position shift amount 52, an image without distortion of the part D2 held by the nozzle 8b can be obtained in the combined image 62. In this example, the center 62c of the combined image 62, the center of the nozzle 8b, and the center of the part D2 are aligned.

The image processing unit 43 stores the combined image 62 as the component imaging result 49 in the mounting storage unit 47. The pickup component position calculation unit 44 calculates the position of the center of the component D2 as viewed from the center of the nozzle 8b (pickup position) based on the stored component imaging result 49 (combined image 62). In this way, in the case of the component D2 that straddles multiple adjacent imaging fields B1 and B2, the pickup position of the component D2 is calculated from an image of the component D2 without distortion in which the shift of the optical axes 33c and 34c is corrected based on the position shift amount (imaging field position shift amount 52) of the mark 25 in the imaging fields B1 and B2. In this way, the mounting accuracy of the component D2 can be improved by correcting the shift of the optical axes 22d and 23d using the mark 25 that is precisely provided on one transparent plate 24.

As described above, the imaging fields B1 to B8 are arranged in series, and the multiple cameras (first camera units 33A to 33D, second camera units 34A to 34D) that image the component D2, the component recognition camera 32 that has the mark 25 that is within the imaging fields B1 to B8 of the multiple cameras but outside the imaging range (component imaging field 24a) when the multiple cameras image the component D2, and the position deviation amount calculation unit 46 that calculates the position deviation amount (imaging field position deviation amount 52) of the imaging fields B1 to B8 of the multiple cameras based on the imaging results (mark imaging results 51) of the multiple cameras each capturing an image of the mark 25 constitute a component imaging device that can correct the deviation of the optical axes 33c, 34c of the cameras that image the component D2.

Next, the configuration of the component recognition camera 70 having another optical axis refraction section R1 (hereinafter simply referred to as "optical axis refraction section R1") will be described with reference to Figures 16 and 17. Hereinafter, the same components as those in the component recognition camera 20 are given the same reference numerals, and detailed description will be omitted. Inside the housing 71 of the component recognition camera 70, a first camera group G1 consisting of a plurality of first camera units 22 and a second camera group G2 consisting of a plurality of second camera units 23 are arranged.

The optical axis 23d of the multiple second camera units 23 is refracted in the direction of the first mirror 72 arranged below the transparent plate 24 by the second mirror 73 arranged above the second camera units 23. Furthermore, the optical axis 23d is refracted upward by the first mirror 72. The first mirror 72 and the second mirror 73 are each a single mirror extending in the X-axis direction, and are shared by the multiple second camera units 23. Furthermore, the first mirror 72 is a half mirror through which the optical axis 22d of the multiple first camera units 22 passes, and is shared by the multiple first camera units 22.

In Figures 16 and 17, the third illumination unit 31 is installed at a position along the Y axis from the first mirror 72. The light 31a emitted from the third illumination unit 31 is refracted upward by the first mirror 72. In this way, the first mirror 72 and the second mirror 73 (mirrors) form an optical axis refraction unit R1 that guides the image of the part D held in the nozzle 8b to the second camera unit 23 (camera of the second camera group). In addition, the first mirror 72 and the second mirror 73 are each a single mirror that is shared by multiple cameras (second camera unit 23) of the second camera group G2.

Next, the configuration of the third component recognition camera 80 (hereinafter simply referred to as "component recognition camera 80") will be described with reference to Figures 18 and 19. The component recognition camera 80 has only a third camera group G3 consisting of multiple cameras (third camera units 82) arranged in series in one direction (X-axis direction) that capture images of the component D, and differs from the component recognition camera 20, which has the first camera units 22 of the first camera group G1 and the second camera units 23 of the second camera group G2 arranged alternately. Hereinafter, the same components as those of the component recognition camera 20 are given the same reference numerals, and detailed descriptions will be omitted.

Figure 18 shows a schematic diagram of the inside of the component recognition camera 80 seen through the housing 81 of the component recognition camera 80 and the housing of the third camera unit 82. The component recognition camera 80 is equipped with a plurality of third camera units 82 (four in this example) that are arranged in a straight line along the X-axis and form a third camera group G3. The third camera unit 82 has a third imaging section 82a that has an imaging element such as a two-dimensional CMOS sensor inside the housing, and a third lens 82b that is positioned between the component D to be imaged and the third imaging section 82a. A transparent plate 24 having a mark 25 is installed above the third lens 82b.

In Figures 18 and 19, the third camera unit 82 is installed with its optical axis 82c facing upward, and captures the target part D from below. A fourth illumination unit 83 is installed above the third lens 82b in a position that does not interfere with the imaging by the third camera unit 82. The fourth illumination unit 83 is configured with multiple LED chips, etc., and emits light from below to illuminate the target part (such as part D) or the mark 25 on the transparent plate 24.

In FIG. 19(a), the four third camera units 82 of the third camera group G3 are referred to as third camera unit 82A to third camera unit 82D in order from the left in the X-axis direction. In FIG. 19(a) and FIG. 19(b), the third imaging section 82a and the third lens 82b of the third camera units 82A to 82D are optical systems with a large (wide) angle of view. The width in the X-axis direction of the imaging fields C1 to C4 of the third camera units 82A to 82D is approximately twice the size of the width LX1 in the X-axis direction of the imaging fields A1, A3, A5, and A7 of the first camera units 22A to 22D. In the component recognition camera 80, adjacent imaging fields C1 to C4 of the third camera units 82A to 82D partially overlap each other in one direction (X-axis direction).

Figure 19 (c) shows an example of imaging of a 16-nozzle mounting head in which a small component D1 is held by each of 16 nozzles 8b by the component recognition camera 80. The imaging fields C1 to C4 of the third camera units 82A to 82D are designed so that two components D1 pass through each of them. The processing by the component imaging processing unit 42, image processing unit 43, component pickup position calculation unit 44, and mark imaging processing unit 45 is similar to that of the component recognition camera 20 described above, and a description thereof will be omitted. The position deviation amount calculation unit 46 calculates the position deviation amount (imaging field position deviation amount 52) of the imaging fields C1 to C4 of the multiple cameras based on the imaging results of the multiple cameras (third camera units 82A to 82D) each capturing a still image of the mark 25. This corrects the deviation of the optical axis 82c of the third camera units 82A to 82D.

In this way, the imaging fields C1 to C4 are arranged in series, and multiple cameras (third camera units 82A to 82D) that image part D, the part recognition camera 80 having a mark 25 that is located within the imaging fields C1 to C4 of the multiple cameras but outside the imaging range (part imaging field 24a) when the multiple cameras image part D1, and the position deviation calculation unit 46 constitute a part imaging device that can correct the deviation of the optical axis 82c of the camera that images part D1.

The component imaging device of the present invention has the effect of being able to correct the misalignment of the optical axis of the camera that images the component, and is useful in the field of mounting components on a circuit board.

20, 32, 70, 80: Part recognition camera (part imaging device)
22, 22A to 22D, 33A to 33D First camera unit (camera)
23, 23A to 23D, 34A to 34D Second camera unit (camera)
24 Transparent plate 24a Component imaging field of view (imaging range)
25, 25A to 25H Mark 26 First lighting section (lighting section)
29 Second lighting unit (lighting unit)
31 Third lighting section (lighting section)
82, 82A to 82D Third camera unit (camera)
83 4th lighting section (lighting section)
A1-A8, B1-B8, C1-C4 Imaging field of view D, D1, D2 Parts

Claims (5)

A plurality of cameras each having an imaging field of view arranged in series for imaging a component;
a transparent plate disposed between the plurality of cameras and the component;
a mark provided on the transparent plate within the imaging field of view of the plurality of cameras and outside the imaging range when the plurality of cameras images an image of a component;
and a positional deviation amount calculation unit that calculates a positional deviation amount of the imaging fields of the multiple cameras based on imaging results of the multiple cameras capturing images of the marks. The part imaging device according to claim 1 , further comprising an illumination unit that illuminates the mark. The component imaging device according to claim 2 , wherein the illumination unit is provided for each of the plurality of cameras. 4. The component imaging device according to claim 1 , wherein at least two of the marks are provided on the transparent plate in each of the imaging fields of the plurality of cameras. The component imaging device according to claim 4 , wherein the positional deviation amount calculation unit calculates a positional deviation amount of an imaging field of one of the plurality of cameras from positions of at least two of the marks captured in the imaging field of the one of the plurality of cameras.

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