Image acquisition device, circuit board inspection device and image acquisition method

Abstract

An image recording device according to the present disclosure takes pictures of the several target objects arranged on a plane when inspecting several target objects, wherein the image recording device comprises: a camera unit with a camera capable of imaging the several target objects from above and configured to change a focus height at which the camera is in focus;and a control section configured to determine a width in the vertical direction that can be covered by a single image generation of the camera, based on a height difference between a highest target object and a lowest target object among several target objects that can be imaged simultaneously by the camera, and based on a depth of field of the camera, in order to determine a focus height for each image generation and to cause the camera unit to take each image by adjusting the focus so that it is adapted to a respective determined focus height.

Description

Technical field

[0001] The present description discloses an image acquisition device, a circuit board inspection device and an image acquisition method. State of the art

[0002] A conventional image inspection device is known that checks an inspection target using an image and verifies the position or orientation of the inspection target based on images obtained by simultaneously imaging several inspection targets. For example, patent literature 1 discloses a technique for simultaneously imaging one of several inspection objects (hereinafter referred to as the reference object) and an inspection object whose distance from a surface of the reference object is less than the depth of field of a camera. List of cited writings Patent literature

[0003] Patent Literature 1: JP-A-2015-145797 Overview of the invention Technical task

[0004] However, with the image inspection device described above, even if the distance between the multiple inspection targets (excluding the reference target) is less than the camera's depth of field, an inspection target whose distance from the reference target is greater than the camera's depth of field is captured separately from the reference target. For this reason, the number of camera images taken increases, and the time required for image acquisition can lengthen.

[0005] A primary objective of the present disclosure is to reduce the time required for image acquisition.

[0006] The present disclosure uses the following means to solve the main problem described above. Solution to the problem

[0007] An image recording device according to the present disclosure is an image recording device for capturing or acquiring, when inspecting several target objects arranged on one plane, images of the several target objects, wherein the image recording device comprises: a camera unit with a camera designed to image multiple target objects from above, and to change a focus height at which the camera is in focus; and a control section which is designed to determine a width in a vertical direction that can be covered by a single image acquisition or image generation by the camera, based on a height difference between a highest target object and a lowest target object among several target objects that can be imaged by the camera simultaneously, and based on a depth of field of the camera. to obtain in order to determine a focus height for each image generation or image capture and to cause the camera unit to capture each image by setting a focus adapted to a respective specific focus height.

[0008] In this image acquisition device, the width in the vertical direction that can be covered by a single image capture or image generation by the camera is determined based on the height difference and the camera's depth of field to establish a focus height for each image generation. The camera unit is then instructed to capture each image by adjusting the focus to the determined focus height. Accordingly, the number of image generations by the camera can be limited to a maximum of the number corresponding to the ratio of the height difference to the width in the vertical direction. Therefore, the time required to capture the image can be reduced.

[0009] A circuit board inspection device according to the present disclosure is a circuit board inspection device for inspecting an assembly state of several components mounted on a circuit board, wherein the circuit board inspection device comprises: a camera unit with a camera that can image the multiple components from above and is designed to change a focus height at which the camera is in focus; a control section configured to determine a width in a vertical direction that can be covered by a single image acquisition or generation by the camera, based on a height difference between a highest target object and a lowest target object among several target objects that can be imaged simultaneously by the camera, and based on a depth of field of the camera, in order to determine a focus height for each image acquisition and to cause the camera unit to take each image by adjusting the focus so that it corresponds to the respective determined focus height; and an inspection section that is trained to inspect or check the assembly status of the several components on the circuit board based on the images.

[0010] The circuit board inspection device has the same effect as the image acquisition device of the present disclosure.

[0011] An image acquisition method according to the present disclosure is an image acquisition method for capturing images of several target objects arranged on a plane, using a camera unit comprising a camera capable of imaging the several target objects from above and configured to change a focus height at which the camera is in focus, wherein the image acquisition method comprises: obtaining or determining a height range that can be covered by a single image acquisition of the camera, based on a height difference between a tallest target object and a shortest target object among several target objects that can be imaged simultaneously by the camera, and based on a depth of field of the camera, in order to determine a focus height for each image acquisition or image generation; and causing the camera unit to capture or generate each image by adjusting the focus accordingly.to record that it corresponds to each specific focus height.

[0012] This image acquisition method has the same effects as the image acquisition device and the circuit board inspection device of the present disclosure. Brief description of the drawings Fig. Figure 1 is a schematic overview of a component placement system 1. Fig. Figure 2 is a schematic overview of a head lifting and lowering device 50. Fig. Figure 3 is a block diagram illustrating electrical connections in component placement system 1. Fig. Figure 4 is a flowchart illustrating an example of a processing routine for determining the focus height. Fig. Figure 5 is a flowchart illustrating an example of a processing subroutine for setting the image height range. Fig. Figure 6A is a diagram illustrating a method for calculating a height difference ΔH. Fig. 6B is a diagram illustrating a method for calculating a width h in a vertical direction. Fig. Figure 6C is a diagram illustrating a procedure for setting an image height range R. Fig. 6D is a diagram illustrating a procedure for determining the presence or absence of imaging or image generation and the focus height in each imaging height range R. Fig. Figure 7 is a diagram illustrating an example of focus data 63a. Fig. Figure 8 is a flowchart illustrating an example of a processing routine for inspecting components after assembly. Description of embodiments

[0013] An embodiment of the invention of the present disclosure is described below with reference to the drawings. Fig. Figure 1 is a schematic overview of the component placement system 1. Fig. Figure 2 is a schematic overview of the head lifting and lowering device 50. Fig. Figure 3 is a block diagram illustrating electrical connections in component placement system 1. Fig. 1 and Fig. 2 is a left-right direction, an X-axis direction (a direction perpendicular to the drawing plane in Fig. 2) A front-back direction is a Y-axis direction and an up-down direction is a Z-axis direction.

[0014] The component placement system 1 includes a component placement device 10 and a management device 70 (see Fig. 3) on. As in Fig. As shown in Figure 1, the component placement machine 10 picks up component C supplied by a component feeding device 21 and mounts component C onto a circuit board S. As shown in Figure 1. Fig. As shown in Figure 1, the component placement device 10 includes the component feeder 21, a circuit board conveyor 22, a head 40, a head movement device 30, and a head lifting and lowering device 50 (see Figure 1). Fig. 2), a parts camera 24, a marking camera 25 and a control device 60 (see Fig. 3) on.

[0015] The component feeding device 21 includes, for example, a tray feeding device 21a, which feeds a tray with a large number of receiving pockets for receiving components C, a belt feeding device 21b, which feeds a belt with a large number of cavities for receiving components C, and the like.

[0016] The circuit board conveyor 22 transports the circuit board S from left to right by driving two conveyor belts arranged as a pair. For example, the circuit board conveyor 22 includes two conveyor belts arranged as a pair, which are installed at a predetermined distance in the front-back direction (Y-axis direction) and laid out in the left-right direction (X-axis direction).

[0017] The head 40 holds a suction nozzle 41 that captures (picks up) the component C. Although not shown, a vacuum source is connected to the suction nozzle 41 via a solenoid valve (on / off valve), and the suction nozzle 41 picks up the component C by exerting the vacuum generated by the vacuum source. The head 40 has a Z-axis actuator 42 (see Fig. 3) and Z-axis position sensor 43 (see Fig. 3) on. The Z-axis actuator 42 (see Fig. 3) is controlled to move the suction nozzle 41 in the up-down direction (Z-axis direction). The Z-axis position sensor 43 detects the position of the suction nozzle 41 in the Z-axis direction and outputs the detected position to the control device 60 (see Fig. 3).

[0018] The head movement device 30 moves the head 40 in the forward-backward and left-right directions (directions of the X and Y axes). As shown in Fig. As shown in Figure 1, the head movement device 30 has an X-axis carriage 32 and a Y-axis carriage 34. The X-axis carriage 32 is supported by two upper and lower X-axis guide rails 33, arranged as a pair, which are attached to a front face of the Y-axis carriage 34 and extend in the left-right direction (X-axis direction). The X-axis carriage 32 is moved along the X-axis guide rail 33 in the X-axis direction by actuating the X-axis actuator 36 (see Figure 1). Fig. 3) The Y-axis carriage 34 is supported by two pairs of left and right Y-axis rails 35, which are mounted on an upper section of a housing 12 and extend in the front-to-back direction (Y-axis direction). The Y-axis carriage 34 is moved along the Y-axis rail 35 in the Y-axis direction by actuating the Y-axis actuator 38 (see Fig. 3) The position of the X-axis carriage 32 in the X-axis direction is detected by the X-axis position sensor 37 (see Fig. 3) In addition, the position of the Y-axis carriage 34 in the Y-axis direction is detected by the Y-axis position sensor 39 (see Fig. 3) The head 40 is attached to the X-axis carriage 32. Therefore, the head 40 is moved in an XY plane (horizontal plane) by appropriately actuating and controlling the head movement device 30 (X-axis actuator 36 and Y-axis actuator 38).

[0019] The head lifting and lowering device 50 raises and lowers the head 40. As in Fig. As shown in Figure 2, the head lifting and lowering device 50 is mounted on the X-axis sliding carriage 32. The head lifting and lowering device 50 comprises a Z-axis actuator 51, a ball screw 52, ​​a movable body 53, and a Z-axis position sensor 54 (see Figure 2). Fig. 3) The ball screw 52 is designed to extend in the up-down direction (Z-axis direction) and is screwed into a ball nut (not shown) attached to the movable body 53. Therefore, the movable body 53 is raised and lowered in the up-down direction by rotating the ball screw 52 with the Z-axis actuator 51. The movable body 53 also holds the head 40. Accordingly, the head lifting and lowering device 50 moves the movable body 53 up and down by actuating the Z-axis actuator 51, thereby moving the head 40 up and down. The Z-axis position sensor 54 detects the position of the head 40 in the Z-axis direction and outputs the detected position to the control device 60 (see Fig. 3).

[0020] When component C, fed by component feeder 21, is picked up and mounted on the circuit board S transported by circuit board conveyor 22, the component camera 24 takes an image of component C from below as component C passes over the component camera 24. As in Fig. As shown in Figure 1, the parts camera 24 is mounted between the component feeder 21 and the circuit board conveyor 22. The parts camera 24 outputs the captured image to the control device 60 (see Figure 1). Fig. 3).

[0021] The marking camera 25 takes top-down images of the circuit board S being transported by the circuit board conveyor 22, component C being fed by the component feeder 21, component C mounted on the circuit board S, and the like. As in Fig. As shown in Figure 1, the marking camera 25 is attached to the head 40 and is moved along the XY axes together with the head 40 by the head movement device 30. The marking camera 25 is moved along the Z-axis direction together with the head 40 by the head lifting and lowering device 50. The marking camera 25 outputs the captured image to the control device 60 (see Figure 1). Fig. 3).

[0022] As in Fig. As shown in Figure 3, the control device 60 is configured as a microprocessor with a central CPU 61 and, in addition to the CPU 61, has a ROM 62, a memory (e.g., HDD or SSD) 63, and a RAM 64. A position signal from the X-axis position sensor 37, the Y-axis position sensor 39, the Z-axis position sensor 43, or the Zs-axis position sensor 54 is supplied to the control device 60. Additionally, an image signal from the part camera 24 or the marking camera 25 is also supplied to the control device 60. Furthermore, using the image supplied by the part camera 24, the control device 60 calculates a measurement deviation of the component C picked up by the suction nozzle 41 and checks or inspects the assembly status of the component C on the circuit board S using the image supplied by the marking camera 25.Meanwhile, the control device 60 outputs control signals to the component feeder 21, the circuit board conveyor 22, the X-axis actuator 36, the Y-axis actuator 38, the Z-axis actuator 42, and the Zs-axis actuator 51. Additionally, the control device 60 also outputs a control signal to the part camera 24 or the marking camera 25. The memory 63 stores data used for inspecting the circuit board S.

[0023] As in Fig. As shown in Figure 3, the management device 70 is configured as a microprocessor with a central CPU 71 and, in addition to the CPU 71, has a ROM 72, a memory 73, and a RAM 74. The management device 70 is communicatively connected to the control device 60. The memory 73 stores shape data for each component C to be mounted on the circuit board S, a production plan, data on the target mounting position, and the like. The shape data specifies the external shape, including the height, of the component C, the type of component C to be mounted on the circuit board S, and the like. The production plan specifies which components C are to be mounted in which sequence in the component placement machine 10, how many circuit boards S (products) on which such assembly has been carried out are to be produced, and the like. The target mounting position data specifies the position on the circuit board S at which each component C is to be mounted.The target assembly position data includes, for example, a value of an X-axis coordinate and a value of a Y-axis coordinate for each component C, when a predetermined point of the circuit board S is defined as the origin, an angle formed by a long side of component C and a line parallel to the Y-axis, and the like.

[0024] Next, the operation of component placement system 1, which is structured as described above, will be described. First, the component assembly process, performed by the CPU 61 of the component placement machine 10, will be described. The CPU 61 receives an instruction to start production from the management device 70, enters the form data, the production plan, and the data for the target assembly position, stores the form data, the production plan, and the data for the target assembly position in memory 63, and then starts the current processing operation.

[0025] When this processing is started, the CPU 61 causes the suction nozzle 41 to pick up the component C supplied by the component feeder 21. In particular, the CPU 61 controls the head movement device 30 (X-axis actuator 36 and Y-axis actuator 38) such that the suction nozzle 41 moves through the component feeder 21 to a position above the feed position of the component C, controls the Z-axis actuator 42 such that the suction nozzle 41 is lowered, and controls the solenoid valve such that the vacuum is applied to the suction nozzle 41. Next, the CPU 61 mounts component C onto the circuit board S. More precisely, the CPU 61 controls the head movement device 30 so that component C, picked up by the suction nozzle 41, is moved to a position above the mounting position of the circuit board S, controls the Z-axis actuator 42 so that component C is pressed against the circuit board S, and controls the solenoid valve so that the picking up of component C is stopped.The CPU 61 repeatedly performs these processing steps until all components C, which are to be assembled by the component placement machine 10, are assembled.

[0026] Next, the post-assembly component inspection sequence, performed by the CPU 61 of the control device 60 after the component placement process has been completed, is described. When the post-assembly component inspection sequence is started, the CPU 61 controls the head movement device 30 (X-axis actuator 36 and Y-axis actuator 38) such that the marking camera 25 moves to a position above the circuit board S. The CPU 61 then controls the marking camera 25 to capture an image of the circuit board S, including component C. The CPU 61 then designates one of the mounted components C as the target component for inspection. Finally, the CPU 61 processes the captured image and determines the actual mounting position (value of the X-axis coordinate, value of the Y-axis coordinate, and angle) of the target component to be inspected on the circuit board S.Next, CPU 61 calculates a position deviation amount based on the difference between the actual assembly position and the target assembly position. If at least one of the X-axis coordinate, Y-axis coordinate, or angle values ​​exceeds a permissible range, CPU 61 determines that the assembly state of the target component under inspection is not normal. Conversely, if the respective X-axis coordinate, Y-axis coordinate, and angle values ​​are within the permissible range, CPU 61 determines that the assembly state of the target component under inspection is normal. CPU 61 then stores the result of this determination in memory 63. CPU 61 performs these processing steps for all components that are target components under inspection.

[0027] Various types of components C with different heights are mounted on the circuit board S. If the circuit board S is imaged only once in a state where the focus of the marking camera 25 is fixed on a predetermined position, the component C will be imaged in a state where it is not included in the depth of field D of the marking camera 25. There is a risk that the mounting state of the component C, which is imaged in a state where it is not included in the depth of field D of the marking camera 25, will not be determined correctly. Therefore, in the present embodiment, the image height range R (included in the depth of field D of the marking camera 25), which is determined by an image or...To determine the scope of image generation, the focus height P, at which the marker camera 25 is in focus, is determined within the image height range R. The marker camera 25 is focused at each focus height P, the circuit board S is imaged multiple times by the marker camera 25, and the assembly status of component C relative to the circuit board S is inspected based on several images. Here, a processing routine for focus height determination is first used to determine the focus height P with reference to... Fig. 4 to 7 described. Fig. Figure 4 is a flowchart illustrating an example of the processing routine for focus height determination. This processing routine is executed by the CPU 61 of the control device 60 prior to the component placement sequence described above and the component inspection sequence after assembly. The CPU 61 inputs a start instruction from the management device 70, inputs the shape data, production plan, and target assembly position data from the management device 70, stores the shape data, production plan, and target assembly position data in memory 63, and then executes the present routine. If the circuit board S is larger than an imaging area (horizontal direction) of the marking camera 25, it is divided into several areas in the horizontal direction, and then image processing for inspection is performed.

[0028] When the present routine is started, CPU 61 refers to the shape data to obtain the height H of each component C and recognizes the target mounting position of each component C by referencing the target mounting position data (S100). Next, CPU 61 accesses the shape data to determine the height H1 of the component C with the highest height (in the example, in Fig. 6A to determine component C4) among the components C to be mounted on the circuit board S by component placement machine 10 (S105) (see Fig. 6A). The CPU then accesses 61, as in Fig. 6A shows the shape data to determine the height H2 of component C with the lowest height (component C3 in the example). Fig. 6A) to determine among the components C that are contained in the image area in the horizontal direction of the marking camera 25 and that are the inspection target objects (S110). Then the CPU 61 subtracts, as in Fig. Figure 6A shows the height H2 from the height H1 to calculate the height difference ΔH (= H1 - H2) between two components C (S115).

[0029] Next, CPU 61 receives the depth of field D of marker camera 25 (S120). The depth of field D of marker camera 25 is stored in memory 63 beforehand. CPU 61 then calculates a ratio (= ΔH / D) of the height difference ΔH to the depth of field D, calculates the integer value N by rounding up the fraction of the calculated ratio, and stores the integer value N in memory 63 (S125). Then, CPU 61 calculates, as in Fig. 6B shows the width h (= ΔH / N) of the image height range R in the vertical direction by dividing the height difference ΔH by the integer value N (S130).

[0030] Next, CPU 61 introduces a feature in Fig. 5. The processing subroutine shown is for setting the image height range (S135). The processing subroutine for setting the image height range is used for processing the setting of the image height range R.

[0031] When the processing subroutine for setting the image height range is started, CPU 61 first sets the variable k to the value 1 (S300). Next, CPU 61 adds, as in Fig. 6C shows an integrated value of the width h in the vertical direction and (k - 1) to the height H2, in order to calculate the lower final height TBk (= H2 + h × (k - 1)) of the k-th image height range R (S305). The CPU 61 then adds, as shown in Fig. As shown in 6C, an integrated value of the width h in the vertical direction and k in the vertical direction is used to calculate the upper final height TBk (= H2 + h × k) of the k-th image height range R (S310). Then the CPU 61, as shown in Fig. Figure 6C shows a range from the lower end height TBk to the upper end height TUk defined as the k-th image height range R (S315). Fig. 6C indicates the number of circles represented by dashed lines, which represents a sequence of the image height range R. By repeatedly executing these processing steps, the CPU 61 N (three in the Fig. (Example 6C shown) Image height ranges R with the same width (width h) in a range from a surface of component C with the lowest height to a surface of component C with the highest height, when component C is mounted on the board S.

[0032] Next, CPU 61 increments the value of variable k by 1 (S320). Then, CPU 61 determines whether the value of variable k is greater than the integer value N (S325). If the value of variable k is greater than the integer value N, CPU 61 determines that N image height ranges R have not yet been set and makes a negative determination. Conversely, if the value of variable k is greater than the integer value N, CPU 61 determines that N image height ranges R have already been set and makes a positive determination. If a negative determination is made in S325, CPU 61 returns to S305. Conversely, if a positive determination is made in S325, CPU 61 terminates the subroutine for setting the image height range and proceeds to S140 of the program in S305. Fig. The processing routine for focus height determination shown in section 4 continues.

[0033] The CPU 61 then sets the value of the variable i to 1 (S140). The CPU 61 then compares the height H of each component C detected in S100 with the lower end height TBi and the upper end height TBi in the i-th mapping height range R, which was defined by the mapping height range setting processing subroutine, to determine whether a component C with a height (surface area) H exists within the i-th mapping height range R when the component C is mounted on the board S (S145). The CPU 61 determines that the component C with the lowest height H among several components C has a height H within the first mapping height range R, and determines that the component C with the highest height H has a height H within the N-th mapping height range R.If the height H of component C is the height H that coincides with a boundary between adjacent mapping height ranges R, the CPU 61 determines that component C with height (surface) H is contained in one of two adjacent mapping height ranges R.

[0034] If there is no component C with height H within the i-th imaging height range R, CPU 61 makes a negative decision. Conversely, if there is a component C with height H within the i-th imaging height range R, CPU 61 makes a positive decision. If a negative determination is made in S145, CPU 61 decides to skip imaging the i-th imaging height range R in a processing routine for post-assembly component inspection described later and sets the information regarding the presence or absence of imaging or image generation in the i-th imaging height range R to "missing" (S150). Next, CPU 61 decides not to define an image processing target object in the processing routine for post-assembly component inspection described later (S155). Subsequently, CPU 61 decides not to determine the focus height P (S160).

[0035] On the other hand, if a positive determination occurs in S145, CPU 61 determines whether to execute image generation or mapping of the i-th image height range R in the processing routine for component inspection after assembly, which will be described later, and sets the information regarding the presence or absence of mapping in the i-th image height range R to "present" (S165). Subsequently, CPU 61 defines the component C with height H within the i-th image height range R as the image processing target object (S170). Then, CPU 61 determines whether there are two or more components C with height (surface area) H within the i-th image height range R (S175).

[0036] If it is determined that there are two or more components C with height H within the i-th image height range R, CPU 61 makes a positive determination. Conversely, if it is determined that a single component C with height H lies within the i-th image height range R, CPU 61 makes a negative determination. If a positive determination is made in S175, CPU 61 determines the focus height P in the i-th image height range R as the average height of two or more components C (S180). Conversely, if a negative determination is made in S175, CPU 61 determines the focus height P in the i-th image height range R as the height H of component C (S185).

[0037] Here is an example of the processing flow from S145 to S185 with reference to Fig. 6D described. In Fig. 6D indicates the number of circles represented by dashed lines as a sequence of the image height range R. Since components C1, C2, and C3 exist as components C with a height (surface) H within the first image height range R, the CPU 61 sets the information regarding the presence or absence of an image or image generation in the first image height range R to "present" (S165). The CPU 61 then defines components C1, C2, and C3 as the image processing target object of the image captured in the first image height range R (S170). Finally, the CPU 61 determines the focus height P in the first image height range R as the average height (focus height P1) (S180). Furthermore, since there is no component C with height H in the second image height range R, the CPU 61 sets the information regarding the presence or absence of image generation in the second image height range R to "missing" (S150).The CPU 61 then decides not to define the image processing target object (S155). Next, the CPU 61 decides not to define the focus height P in the second image height range R (S160). Since component C4 is the only component C with height H within the third image height range R, the CPU 61 sets the information regarding the presence or absence of an image or image generation in the third image height range R to "present" (S165). The CPU 61 then defines component C4 as the image processing target object of the image captured in the third image height range R (S170). Finally, the CPU 61 determines the focus height P in the third image height range R as the height (focus height P3) of component C4 (S185).

[0038] Next, the CPU stores 61, as in Fig. Figure 7 shows that memory 63 contains information regarding the image height range R (the i-th), information regarding the presence or absence of image generation, the focus height P, and the image processing target object in the i-th image height range R, which are mapped to each other (S190). Then, CPU 61 increments the value of variable i by 1 (S195). CPU 61 then determines whether the value of variable i is greater than the integer value N (S195). If the value of variable i is equal to or less than the integer value N, CPU 61 determines that there is still one image height range R in which the information about the presence or absence of image generation and the focus height P must be set, and makes a negative decision.If, on the other hand, the value of the variable i is greater than the integer value N, the CPU 61 determines that the information regarding the presence or absence of image generation and the focus height P has been determined for all image height ranges R, and makes a positive determination. If a negative determination is made in S190, the CPU 61 returns to S145. If, on the other hand, a positive determination is made in S190, the CPU 61 terminates the current routine. In the present embodiment, data obtained by repeatedly executing the processing from S145 to S175 are referred to as focus data 63a.

[0039] Next, the procedure for the post-assembly inspection is described, which is carried out by the CPU 61 of the control device 60 after the component placement machine 10 has mounted the component C on the circuit board S in the component placement procedure described above. Fig. Figure 8 is a flowchart that illustrates an example of the processing routine for post-assembly inspection.

[0040] When the present routine is started, CPU 61 sets the value of the variable i to 1 (S400). Next, CPU 61 controls the head movement device 30 such that the marker camera 25 moves to a position above the circuit board S (S405). Then, CPU 61 accesses the in Fig. The CPU 61 uses the focus data 63a shown in S410 to obtain information about the presence or absence of imaging in the i-th image height range R. It then determines whether the information about the presence or absence of image generation acquired in S410 is "present" (S415). If the information about the presence or absence of image generation acquired in S410 is "missing," the CPU 61 decides to skip image generation in the i-th image height range R and makes a negative decision. Conversely, if the information about the presence or absence of image generation acquired in S410 is "present," the CPU 61 decides to perform image generation in the i-th image height range R and makes a positive decision. If a negative determination is made in S415, the CPU 61 proceeds to S465. If, on the other hand, a positive determination occurs in S415, CPU 61 accesses the data in Fig. The CPU 61 uses the focus data 63a shown in Figure 7 to determine the focus height P in the i-th image height range R (S420). Then, the CPU 61 sets a target object height of the head 40 such that the focus height of the marker camera 25 matches the focus height P determined in S420, and controls the head lifting and lowering device 50 (Zs-axis actuator 51) so that the head 40 moves to the target object height (S425).

[0041] Next, the CPU 61 controls the marker camera 25 so that the image of circuit board S is captured (S430). The CPU 61 then accesses the... Fig. The CPU 61 uses the focus data 63a shown in S430 to identify component C, which is the image processing target object of the image captured in the i-th image height range R (S435). Then, the CPU 61 processes the image captured in S430 to calculate the magnitude of the positional deviation of component C (S440).

[0042] Next, the CPU 61 determines whether the amount of the positional deviation of component C, as determined in S440, is within the permissible range (S445). If the determination in S445 is positive, it is determined that the assembly condition is normal (S450). Conversely, if the determination in S445 is negative, it is determined that the assembly condition is abnormal (S455). In the present embodiment, the processing in steps S435 to S455 is referred to as inspection processing. The specific content of the inspection processing is described above. After S450 or S455, the CPU 61 stores the result of the determination in memory 63 (S460).

[0043] Next, CPU 61 increments the value of variable i by 1 (S465). Then, CPU 61 determines whether the value of variable i is greater than the integer value N (S470). The integer value N is stored in memory 63 in S125 of the focus height determination processing routine. If the value of variable i is equal to or less than the integer value N, CPU 61 determines that there is an image height range R for which information about the presence or absence of image generation has not yet been acquired, and that there is a component C that is not subject to inspection processing, and makes a negative determination.If, on the other hand, the value of variable i is greater than the integer value N, CPU 61 determines that it has acquired the information regarding the presence or absence of image generation in all image height ranges R and that the inspection processing has been performed on all components C, and makes a positive determination. If a negative determination is made in S470, CPU 61 returns to S410. If, on the other hand, a positive determination is made in S470, CPU 61 terminates the current routine.

[0044] In the component placement machine 10, the focus height is set for each image height range R, which is subdivided according to the depth of field D of the marking camera 25 with respect to the height range from the lowest component C to the highest component C, and an image generation or imaging operation is performed. If, in S145 of the focus height determination processing routine, it is determined that there is no component C with a height H within the image height range R, the CPU 61 sets the presence or absence of image generation in the image height range R to "missing". Subsequently, in the processing routine for component inspection after assembly, if the information regarding the presence or absence of image generation is "missing", the CPU 61 skips the processing of S420 to S460 (image of the board S).Therefore, the number of image generations with the marker camera 25 can be reduced and the time required to capture the image can be shortened.

[0045] This clarifies a correspondence between the elements of the present embodiment and the elements of the present disclosure. That is, the component placement device 10 of the present embodiment corresponds to an image acquisition device of the present disclosure, the marking camera 25 and the head lifting and lowering device 50 correspond to a camera unit of the image acquisition device, and the CPU 61, which performs the processing of S105 to S180 of the focus height determination processing routine, corresponds to a control section of the image acquisition device.Furthermore, the component placement device 10 corresponds to a circuit board inspection device of the present disclosure, the marking camera 25 and the head lifting and lowering device 50 correspond to a camera unit of the circuit board inspection device, the CPU 61, which performs the processing of S105 to S165 of the focus height determination processing routine, corresponds to a control section of the circuit board inspection device, and the CPU 61, which performs the processing routine for component inspection after assembly, corresponds to an inspection section.

[0046] In the component placement machine 10 described in detail above, the width in the vertical direction that can be covered by a single image capture or image generation by the camera is determined, the focus height of each image generation is determined, and the camera unit is instructed to capture each image by adjusting the focus to the respective specified focus height. Based on the height difference ΔH and the depth of field D of the marking camera 25, the width h in the vertical direction that can be covered by a single image capture by the marking camera 25 is determined, the focus height of each individual image capture or image generation is determined, and the marking camera 25 and the head lifting and lowering device 50 are instructed to capture each image by adjusting the focus to the respective specified focus height.Accordingly, the number of images taken with the marker camera 25 can be set to a maximum of the number corresponding to the ratio of the height difference ΔH to the width h in the vertical direction. Therefore, the number of images taken with the marker camera 25 can be reduced, and the time required for taking images with the marker camera 25 can be shortened.

[0047] In the component placement machine 10, the integer value N of the ratio of the height difference ΔH to the depth of field D of the marking camera 25 is calculated, and the height difference ΔH is divided uniformly by the integer value N to obtain the width h in the vertical direction. Accordingly, the width h in the vertical direction can be set to a suitable length.

[0048] Furthermore, in the component placement machine 10, each image height range R covered by each image generation time is defined between the tallest component C and the shortest component C based on the width h in the height direction, and each focus height P is determined within each image height range R. As a result, it is possible to define the frequency of image generations that is just sufficient to image all components C based on the width h in the height direction.

[0049] In addition, in the component placement machine 10, if none of the components C is contained in one of the image height ranges R, image acquisition within the corresponding image height range R is skipped. Accordingly, the number of imaging operations using the marking camera 25 can be further reduced.

[0049] If several components C are contained within one of the image height ranges R, the component placement device 10 determines the focus height in the corresponding image height range R as the average height of several components C contained within that range. Accordingly, several components C can be imaged at a position closer to the focus position of the lens in the marking camera 25.

[0050] It goes without saying that the present disclosure is in no way limited to the embodiment described above and can therefore be practiced with different properties, as long as the properties fall within the technical scope of the present disclosure.

[0051] In the embodiment described above, the focus height determination processing routine is executed by the CPU 61 of the control device 60. However, the focus height determination processing routine can also be executed by the CPU 71 of the management device 70.

[0052] In the embodiment described above, the focus height P in the imaging height range R is determined based on the number of components C contained in the imaging height range R. However, the focus height P in the imaging height range R can be a constant position determined for each imaging height range R, regardless of the number of components C with a height (surface area) H within the imaging height range R. In this case, the focus height P can be a mean height in the vertical direction in each imaging height range R.

[0053] In the embodiment described above, the lower end height TBk of the k-th image height range R is calculated by adding the integrated value of the width h in the vertical direction and (k - 1) to the height H2, and the upper end height TBk of the k-th image height range R is calculated by adding the integrated value of the width h in the vertical direction and k to the height H2. However, the lower end height TBk of the k-th image height range R can also be calculated by subtracting the integrated value of the width h in the vertical direction and k from the height H1, and the upper end height TUk of the k-th image height range R can be calculated by subtracting the integrated value of the width h in the vertical direction and (k - 1) from the height H1.

[0054] In the embodiment described above, the component inspection process after assembly is carried out by the component placement machine 10. However, the component inspection process after assembly can be carried out using a dedicated inspection device (for example, a device for inspecting the appearance).

[0055] In the embodiment described above, component inspection can be performed after assembly on component C, which was mounted by the component placement machine 10. Alternatively, in a component placement production line with multiple component placement machines 10, component inspection can be performed after assembly on components C that were mounted by the component placement machine 10 located upstream of the component placement machine 10. In this case, component inspection after assembly can be performed by the component placement machine 10 located furthest downstream in the production line.

[0056] In the embodiment described above, the present disclosure is described as a component placement device 10, but it can also be an image acquisition method.

[0057] The present description also discloses a technical concept in which "the image acquisition device according to claim 3" in claim 5, as originally filed, has been amended to "the image acquisition device according to claim 3 or 4". The present description also discloses a technical concept in which "the image acquisition device according to claim 1 or 2" in claim 6, as originally filed, has been amended to "the image acquisition device according to any one of claims 1 to 5". Industrial applicability

[0058] The present disclosure can be applied to the manufacturing industry in the form of a component placement machine, a component placement system and the like. List of reference symbols

[0059] 1: Component placement system, 10: Component picker, 12: Housing, 21: Component feeder, 21a: Tray feeder, 21b: Belt feeder, 22: Circuit board conveyor, 24: Parts camera, 25: Marking camera, 30: Head movement device, 32: X-axis carriage, 33: X-axis guide rail, 34: Y-axis carriage, 35: Y-axis guide rail, 36: X-axis actuator, 37: X-axis position sensor, 38: Y-axis actuator, 39: Y-axis position sensor, 40: Head, 41: Suction nozzle, 42: Z-axis actuator, 43: Z-axis position sensor, 50: Head lifting and lowering device 51: Z-axis actuator, 52: ball screw, 53: moving body, 54: Z-axis position sensor, 60: control device, 61: CPU, 62: ROM, 63: memory, 63a: focus data, 64: RAM, 70: management device, 71: CPU, 72: ROM, 73: memory, 74: RAM, C, C1 to C4: component, D: depth of field orDepth of field, H1: height, H2: height, N: integer value, P, P1, P3: focus height, R: image height range, S: circuit board, ΔH: height difference. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP-A-2015-145797

[0003]

Claims

[1] An image acquisition device for capturing images of several target objects arranged on one plane, the image acquisition device comprising: a camera unit with a camera capable of imaging multiple target objects from above and designed to change the focus height at which the camera is in focus; and a control section designed to obtain a width in a vertical direction that can be covered by a single image generation of the camera, based on a height difference between a highest target object and a lowest target object among several target objects that can be imaged simultaneously by the camera, and a depth of field of the camera, in order to determine a focus height for each image generation and to cause the camera unit to take each image by setting a focus adapted to a respective specific focus height. [2] The image acquisition device according to claim 1, wherein the control section is configured to calculate an integer value of a ratio of the height difference to the depth of field and to divide the height difference uniformly by the integer value to obtain the width in the vertical direction. [3] The image acquisition device according to claim 1 or 2, wherein the control section is configured to adjust each image height range covered by each image generation between the highest target object and the lowest target object based on the width in the vertical direction and to determine each focus height within each image height range. [4] The image acquisition device according to claim 3, wherein the control section is configured to skip the image acquisition within a corresponding image acquisition height range in a case where none of the target objects is contained in one of the image acquisition height ranges. [5] The image acquisition device according to claim 3, wherein the control section is configured to determine, in a case where the multiple target objects are contained in one of the image height ranges, a focus height in a corresponding image height range as an average height of the multiple target objects contained in the corresponding image height range. [6] The image recording device according to claim 1 or 2, wherein the camera unit has a lifting and lowering section designed to change the focus height by raising and lowering the camera, and The control section is designed to control the lifting and lowering section in such a way that the camera moves into a lifting and lowering position corresponding to the determined focus height. [7] A circuit board inspection device for inspecting the assembly state of several components mounted on a circuit board, the circuit board inspection device comprising: a camera unit with a camera capable of imaging the multiple components from above, and designed to change a focus height at which the camera is in focus; a control section configured to determine a width in a vertical direction that can be covered by a single image acquisition of the camera, based on a height difference between a highest target object and a lowest target object among several target objects that can be imaged simultaneously by the camera, and a depth of field of the camera, in order to determine a focus height for each image acquisition and to cause the camera unit to take each image by setting a focus adapted to a respective specific focus height; and an inspection section trained to inspect the assembly status of the multiple components on the circuit board based on the images. [8] An image acquisition method for taking pictures of multiple target objects during the inspection of the multiple target objects arranged on a plane, using a camera unit comprising a camera capable of imaging the multiple target objects from above and configured to change a focus height at which the camera is in focus, the image acquisition method comprising: Determining a height range that can be covered by a single camera image acquisition, based on a height difference between a highest and lowest target object among multiple target objects that can be imaged simultaneously by the camera, and based on a depth of field of the camera, in order to determine a focus height for each image acquisition; and To cause the camera unit to capture each image by adjusting the focus to correspond to each specified focus height.

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