Component mounter and component imaging method

Abstract

To enable imaging of a component while suppressing a difference in illumination conditions caused by a difference in the moving direction of the component relative to an imaging element.SOLUTION: From among two camera triggers Trb and Trc that are output in succession, the center Ct of the trigger interval It, which is the time interval between the camera trigger Trb (first trigger) that is output first and the camera trigger Trc (second trigger) that is output after the camera trigger Trb, is estimated (step S107), and the center Ce of the exposure period Pe is set on the basis of the center Ct of the trigger interval It (step S108).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a component mounting technique for mounting components on a board, and more particularly to a technique for imaging a component in order to recognize the component. [Background technology]

[0002] In component mounting technology for mounting components on a board, the components are recognized based on an image of the components, and the mounting position of the components on the board is adjusted based on the result of the recognition. In contrast, Patent Documents 1 to 4 disclose technologies for capturing images of components using a camera. For example, in Patent Document 1, the components are captured by moving the components in an imaging area and causing the camera to perform exposure every time a trigger is output. Also, as shown in Patent Document 4, a line sensor can be used to capture the images of the components. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-136315 A [Patent Document 2] JP 2020-136361 A [Patent Document 3] JP 2005-159210 A [Patent Document 4] JP 2006-294977 A Summary of the Invention [Problem to be solved by the invention]

[0004] In other words, the entire part can be imaged by repeatedly outputting a trigger at a time interval according to the moving speed of the part and exposing the camera every time the trigger is output. However, as pointed out in Patent Document 4, in the method using a line sensor, the timing of illuminating the part differs depending on the moving direction of the part relative to the line sensor, which may result in differences in the recognition accuracy of the part. Patent Document 4 addresses this by matching the center of the illumination period from when the illumination is turned on to when it is turned off with the center of the trigger output interval.

[0005] However, when using illumination such as a laser that requires time to become stable after being turned on or when the exposure period is extremely short, the method of Patent Document 4 cannot be used. In addition, such a problem also occurs when an area sensor is used instead of a line sensor and an image of a component is captured while a linear ROI (Region Of Interest) is set on the area sensor.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to make it possible to image a component while suppressing differences in illumination conditions caused by differences in the direction in which the component moves relative to an imaging element. [Means for solving the problem]

[0007] The component mounting machine of the present invention includes a camera having an image sensor that captures an image of an imaging range extended in a line, a component movement unit that moves components relative to the imaging range, an illumination unit that illuminates the imaging range by turning on, a trigger output unit that outputs a trigger in response to movement of the components by the component movement unit, and an exposure control unit that causes the camera to expose the image sensor during an exposure period in response to the output of a trigger by the trigger output unit, wherein the illumination unit is turned on for a lighting period that is longer than the exposure period and includes the exposure period, and the exposure control unit estimates the center of a trigger interval, which is the time interval between a first trigger that is output first and a second trigger that is output after the first trigger, of two triggers that are output in succession, and sets the center of the exposure period based on the center of the trigger interval.

[0008] The component imaging method of the present invention includes the steps of moving a component relative to an imaging range of a camera having an imaging element that images an imaging range extended in a line, turning on the illumination unit to irradiate the imaging range from the illumination unit, outputting a trigger in accordance with the movement of the component relative to the imaging range, setting an exposure period in accordance with the trigger, and causing the camera to expose the imaging element during the exposure period, wherein the illumination unit is lit for a lighting period that includes the exposure period and is longer than the exposure period, and in the step of setting the exposure period, a center of a trigger interval, which is the time interval between a first trigger that is output first and a second trigger that is output after the first trigger, of two triggers that are output in succession, is estimated, and the center of the exposure period is set based on the center of the trigger interval.

[0009] In the present invention (component mounter and component imaging method) configured in this manner, the center of a trigger interval, which is the time interval between a first trigger that is output first and a second trigger that is output after the first trigger, of two triggers that are output in succession, is estimated, and the center of the exposure period is set based on the center of the trigger interval. This suppresses bias in the exposure period relative to the trigger interval. Then, the illumination unit is turned on for a lighting period that includes the exposure period and is longer than the exposure period, that is, illumination is continuously applied to the component during the exposure period. As a result, it is possible to image the component while suppressing differences in illumination conditions due to differences in the direction in which the component moves relative to the imaging element.

[0010] The component mounter may be configured such that the trigger output unit sequentially outputs multiple triggers during a period when the component passes through the imaging range, the exposure control unit sets multiple exposure periods according to the multiple triggers, and the illumination unit is continuously lit during a lighting period including the multiple exposure periods. In this configuration, the illumination unit is lit throughout the multiple exposure periods respectively set for the multiple triggers, and the component can be imaged while irradiating the component with stable illumination.

[0011] The exposure control unit may configure the mounter so as to maintain the relationship between the center of the trigger interval and the center of the exposure period regardless of changes in the length of the exposure period. In this configuration, even if the length of the exposure period changes, it is possible to image the component while suppressing differences in illumination conditions caused by differences in the direction of movement of the component relative to the imaging element.

[0012] The mounter may be configured such that the exposure control unit estimates the center of the trigger interval between the first trigger and the second trigger based on the time interval between the first trigger and a third trigger that is output consecutively after the first trigger and before the first trigger. With this configuration, the center of the trigger interval between two triggers that sandwich the exposure period can be appropriately set based on two triggers that are output consecutively immediately before the exposure period.

[0013] The component mounter may be configured such that the exposure control unit estimates the center of the trigger interval between the first trigger and the second trigger based on the relative moving speed of the component with respect to the imaging range. In this configuration, the center of the trigger interval between the two triggers sandwiching the exposure period can be appropriately set based on the moving speed of the component.

[0014] The exposure control unit may configure the mounter so as to set the exposure period so that the center of the trigger interval coincides with the center of the exposure period. With this configuration, it becomes possible to capture images of components under roughly equal illumination conditions regardless of differences in the direction of movement of the components relative to the imaging element. Effect of the Invention

[0015] As described above, according to the present invention, it is possible to image a component while suppressing differences in illumination conditions caused by differences in the moving direction of the component relative to the imaging element. [Brief description of the drawings]

[0016] [Figure 1] 1 is a plan view showing a schematic configuration of an example of a component mounter according to the present invention; [Diagram 2] FIG. 2 is a block diagram showing an electrical configuration of the component mounter of FIG. 1. [Diagram 3] FIG. 2 is a diagram illustrating a mounting head and a component recognition unit included in the component mounter. [Figure 4A] FIG. 4 is a diagram illustrating an image of a component captured by a component recognition camera. [Figure 4B] FIG. 4 is a diagram illustrating an image of a component captured by a component recognition camera. [Figure 5A] 11 is a timing chart showing a comparative example of exposure period control. [Figure 5B] 11 is a timing chart showing a comparative example of exposure period control. [Figure 6] 5 is a flowchart showing a first example of exposure control. [Figure 7] FIG. 7 is a block diagram showing an electrical configuration for executing the flowchart of FIG. 6. [Figure 8] 7 is a timing chart showing the details of calculations executed in the exposure control of FIG. 6; [Figure 9A] 7 is a timing chart showing a schematic result of the exposure control in FIG. 6. [Figure 9B] 7 is a timing chart showing a schematic result of the exposure control in FIG. 6. [Figure 10] 10 is a flowchart showing a second example of exposure control. [Figure 11] FIG. 11 is a block diagram showing an electrical configuration for executing the flowchart of FIG. 10 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Fig. 1 is a plan view showing a schematic configuration of an example of a component mounter according to the present invention, Fig. 2 is a block diagram showing an electrical configuration of the component mounter of Fig. 1, and Fig. 3 is a schematic diagram showing a mounting head and a component recognition unit of the component mounter. In this specification, the X direction, which is a horizontal direction, the Y direction, which is a horizontal direction perpendicular to the X direction, and the Z direction, which is a vertical direction, are appropriately indicated. This component mounter 2 mounts small piece-like electronic components E, such as integrated circuits, transistors, and capacitors, on a board B.

[0018] 2, the component mounter 2 includes a controller 3 that performs overall control of the component mounter 2. The controller 3 includes a main control unit 31, which is a processor including a central processing unit (CPU) and a random access memory (RAM), and a storage unit 32 including a hard disk drive (HDD) or a solid state drive (SSD). The controller 3 also includes a drive control unit 33 that controls a drive system of the component mounter 2, and the main control unit 31 controls the drive system using the drive control unit 33 to perform component mounting for mounting a component E on a board B. The controller 3 also includes an imaging control unit 34 that controls imaging of the component E by a component recognition unit 4, which will be described later, and a communication unit 35 that communicates with an external device such as a management server.

[0019] 1, the component mounter 2 includes a transport unit 21 that transports the board B in the X direction (board transport direction). The transport unit 21 has a pair of conveyors 211 arranged in parallel in the X direction, and transports the board B in the X direction by the conveyors 211. The interval between the conveyors 211 can be changed in the Y direction (width direction) perpendicular to the X direction, and the transport unit 21 adjusts the interval between the conveyors 211 according to the width of the board B to be transported. The transport unit 21 transports the board B from the upstream side in the X direction, which is the board transport direction, to a predetermined work position 212, and transports the board B on which the components E have been mounted at the work position 212 from the work position 212 to the downstream side in the X direction.

[0020] In this component mounter 2, a total of four component supply carts 22 are provided, and specifically, two component supply carts 22 are arranged in the X direction on each side of the transport section 21 in the Y direction. In each component supply cart 22, a plurality of tape feeders 23 are arranged in the X direction, and a plurality of component supply reels are arranged corresponding to the plurality of tape feeders 23, respectively. A component storage tape is wound around the component supply reel. This component storage tape has a plurality of pockets arranged in a row, and a component E is stored in each pocket. Each tape feeder 23 has a component supply position 231 at the tip portion on the transport section 21 side in the Y direction, and supplies the component E in the component storage tape to the component supply position 231 by intermittently feeding the component storage tape pulled out from the component supply reel to the transport section 21 side.

[0021] Further, in the component mounter 2, a pair of Y-axis rails 241 extending in the Y direction, a Y-axis ball screw 242 extending in the Y direction, and a Y-axis motor My for rotating the Y-axis ball screw 242 are provided, and an X-axis rail 244 is fixed to a nut of the Y-axis ball screw 242 while being supported by the pair of Y-axis rails 241 so as to be movable in the Y direction. An X-axis ball screw 245 extending in the X direction and an X-axis motor Mx for rotating the X-axis ball screw 245 are attached to the X-axis rail 244. The component mounter 2 includes a head unit 25, and the head unit 25 is fixed to a nut of the X-axis ball screw 245 while being supported by the X-axis rail 244 so as to be movable in the X direction. Therefore, the drive control unit 33 can rotate the Y-axis ball screw 242 by the Y-axis motor My to move the head unit 25 in the Y direction, or rotate the X-axis ball screw 245 by the X-axis motor Mx to move the head unit 25 in the X direction.

[0022] 1, head unit 25 is an inline type having multiple mounting heads 5 arranged in a line in the X direction. However, the specific configuration of head unit 25 is not limited to the example in Fig. 1, and head unit 25 may be a rotary type having multiple mounting heads 5 arranged in a circular pattern. Furthermore, the number of mounting heads 5 that head unit 25 has is not limited to multiple, and may be a single head.

[0023] A nozzle 51 (FIG. 3) is detachably attached to the lower end of the mounting head 5, and the mounting head 5 picks up the component E by means of the nozzle 51. Meanwhile, the component mounter 2 has a Z-axis motor Mz that raises and lowers the mounting head 5 in the Z direction, and an R-axis motor Mr that rotates the mounting head 5. The drive control unit 33 adjusts the height of the mounting head 5 (i.e., the height of the nozzle 51) by the Z-axis motor Mz, and adjusts the rotation angle of the mounting head 5 (i.e., the rotation angle of the nozzle 51) by the R-axis motor Mr.

[0024] In the component mounter 2, the drive control unit 33 executes control upon receiving a command from the main control unit 31, so that the component E is mounted on the board B. That is, the drive control unit 33 moves the mounting head 5 by the X-axis motor Mx and the Y-axis motor My, so that the nozzle 51 of the mounting head 5 faces the component E supplied to the component supply position 231 from above. Next, the drive control unit 33 lowers the nozzle 51 by the Z-axis motor Mz, so that the nozzle 51 abuts against the upper surface of the component E supplied to the component supply position 231, and then the nozzle 51 adsorbs the component E. Furthermore, the drive control unit 33 raises the nozzle 51 by the Z-axis motor Mz. In this way, the head unit 25 picks up the component E from the component supply position 231 by the nozzle 51 of the mounting head 5. Next, the drive control unit 33 moves the mounting head 5 using the X-axis motor Mx and the Y-axis motor My, thereby causing the component E to be picked up by the nozzle 51 of the mounting head 5 to face the land of the board B from above. Furthermore, the drive control unit 33 adjusts the angle of the component E picked up by the nozzle 51 with respect to the land using the R-axis motor Mr, and then lowers the nozzle 51 using the Z-axis motor Mz, thereby placing the component E on the land of the board B.

[0025] The component mounter 2 also includes a component recognition unit 4 disposed between the two component supply carts 22 in the X direction. The component recognition unit 4 includes a component recognition camera 41 that faces upward and captures an image within an imaging range V41, and an illumination unit 43 that irradiates illumination (light) onto the imaging range V41. The component recognition unit 4 is disposed on both sides of the transport unit 21 in the Y direction. The illumination unit 43 has a plurality of point light sources arranged, for example, in a matrix, and irradiates illumination onto the imaging range V41 by emitting light from each point light source onto the imaging range V41. For example, a laser diode (LD) or a light-emitting diode (LED) can be used as such a point light source.

[0026] When the nozzle 51 of the mounting head 5 picks up the component E from the component supply position 231, the drive control unit 33 moves the component E in the X direction so that the component E passes through the imaging range V41 of the component recognition camera 41 before placing the component E on the board B. Then, as described later, the component recognition camera 41 repeatedly captures the image of the imaging range V41 to obtain a component recognition image Ir showing the entire component E. This component recognition image Ir is stored in the storage unit 32 from the component recognition camera 41 via the imaging control unit 34. In addition, the main control unit 31 performs component recognition to recognize the position of the component E based on the component recognition image Ir stored in the storage unit 32. Specifically, the main control unit 31 recognizes the position of the component E relative to the nozzle 51 based on the position of the nozzle 51 at the time of acquiring the component recognition image Ir and the position of the component E in the component recognition image Ir. The main control unit 31 can confirm the position of the nozzle 51 at the time of acquiring the component recognition image Ir by receiving the encoder output of each of the motors Mx, My, and Mr from the drive control unit 33. Then, the main control unit 31 controls each of the motors Mx, My, and Mr according to the position of the component E recognized based on the component recognition image Ir, thereby adjusting the position of the component E relative to the land of the board B and mounting the component E on the land.

[0027] 4A and 4B are diagrams that show the imaging of a component by a component recognition camera. In FIG. 4A and FIG. 4B, a first direction X1 facing one side of the X direction and a second direction X2 facing the other side of the X direction are shown. That is, the first direction X1 and the second direction X2 are parallel to the X direction and face in opposite directions to each other. The component recognition camera 41 has an image sensor 411 that captures an image of the component E in the imaging range V41 by receiving light reflected by the component E in the imaging range V41. In this example, the image sensor 411 is a line sensor composed of solid-state imaging elements that extend parallel to the Y direction. Therefore, the imaging range V41 extends parallel to the Y direction.

[0028] In the example of FIG. 4A, the drive control unit 33 moves the component E held by the nozzle 51 of the mounting head 5 in the first direction X1. As a result, the component E to be imaged moves in the first direction X1 relative to the imaging range V41. Then, the imaging range V41 is scanned by the component E during a period from when the end of the component E in the first direction X1 reaches the imaging range V41 as shown in "scanning start" of FIG. 4A until the end of the component E in the second direction X2 reaches the imaging range V41 as shown in "scanning end" of FIG. 4A. The component recognition camera 41 acquires an entire image (component recognition image Ir) of the component E by capturing an image of one line (line image) detected by the image sensor 411 each time the component E moves in the first direction X1 by the width of the imaging range V41 while turning on the illumination unit 43 to irradiate the imaging range V41 with illumination from the illumination unit 43.

[0029] In the example of FIG. 4B, the drive control unit 33 moves the component E held by the nozzle 51 of the mounting head 5 in the second direction X2. As a result, the component E to be imaged moves in the second direction X2 relative to the imaging range V41. Then, the imaging range V41 is scanned by the component E during a period from when the end of the component E in the second direction X2 reaches the imaging range V41 as shown in "scanning start" of FIG. 4B until the end of the component E in the first direction X1 reaches the imaging range V41 as shown in "scanning end" of FIG. 4B. The component recognition camera 41 captures an image of the entire component E (component recognition image Ir) by capturing an image of one line (line image) detected by the image sensor 411 each time the component E moves in the second direction X2 by the width of the imaging range V41 while irradiating the imaging range V41 with light from the illumination unit 43.

[0030] 4A and 4B, in order to acquire an image of the component E (component recognition image Ir), the component recognition camera 41 controls the exposure of the image sensor 411 by using a shutter. That is, during a period in which the imaging range V41 is scanned with respect to the component E, the component recognition camera 41 opens the shutter with respect to the image sensor 411 to allow light reflected by the imaging range V41 to reach the image sensor 411 (that is, exposes the image sensor 411). As a result, during an exposure period in which the shutter is open, the image sensor 411 is exposed to light from the imaging range V41, and an image of the component E passing through the imaging range V41 (component recognition image Ir) is captured. On the other hand, during a period in which the imaging range V41 is not scanned with respect to the component E, the component recognition camera 41 closes the shutter with respect to the image sensor 411 to restrict the light reflected by the imaging range V41 from reaching the image sensor 411.

[0031] Specifically, the imaging control unit 34 receives the output of the encoder of the X-axis motor Mx that moves the part E in the X direction from the drive control unit 33, generates a trigger synchronized with the encoder output, and the part recognition camera 41 sets an exposure period for opening the shutter based on the trigger received from the imaging control unit 34. However, there are circumstances as shown in Figs. 5A and 5 that affect the setting of this exposure period.

[0032] 5A and 5B are timing charts showing a comparison example of the control of the exposure period, in which FIG. 5A shows a case where the part E is imaged while moving the part E in the first direction X1, and FIG. 5B shows a case where the part E is imaged while moving the part E in the second direction X2. In both examples of FIG. 5A and FIG. 5B, the imaging control unit 34 generates a camera trigger Tr every time the part E moves by the width of the imaging range V41 relative to the imaging range V41. In addition, the part recognition camera 41 sets the exposure period Pe so that the exposure period Pe starts at a point when a predetermined time Δ has elapsed since the generation of the camera trigger Tr. As a result, a plurality of exposure periods Pe are set. In addition, the imaging control unit 34 sets a lighting period Pi in which the illumination unit 43 is turned on to irradiate the imaging range V41 with illumination. This lighting period Pi is set to include a plurality of exposure periods Pe, and the illumination unit 43 irradiates the imaging range V41 with illumination throughout the lighting period Pi.

[0033] When the exposure period Pe is set in this way, the position of the light (exposure reflected light) reflected by the part E in the imaging range V41 and used to expose the image sensor 411 on the part E differs between the case where the part E is moved in the first direction X1 and the case where the part E is moved in the second direction X2. That is, as shown in FIG. 5A, when the part E is moved in the first direction X1, the exposure reflected light is biased toward the first direction X1 side, and as shown in FIG. 5B, when the part E is moved in the second direction X2, the exposure reflected light is biased toward the second direction X2 side. Due to such a bias in the reflection position of the light (in other words, a difference in light distribution), a difference occurs in the image (part recognition image Ir) of the part E between the case where the part E is moved in the first direction X1 and the case where the part E is moved in the second direction X2, which may affect the recognition accuracy of the part E. In this embodiment, in order to deal with such a situation, the exposure control described below is executed.

[0034] FIG. 6 is a flowchart showing a first example of exposure control, FIG. 7 is a block diagram showing the electrical configuration for executing the flowchart of FIG. 6, FIG. 8 is a timing chart showing typically the calculation contents performed in the exposure control of FIG. 6, and FIGS. 9A and 9B are timing charts showing typically the results of the exposure control of FIG. 6.

[0035] As shown in FIG. 7, the drive control unit 33 has a servo control unit 331 that executes servo control on the X-axis motor Mx. The servo control unit 331 executes feedback control on the X-axis motor Mx based on the difference between the speed Vxe in the X direction of the mounting head 5 indicated by the output of the encoder of the X-axis motor Mx and the speed command value Vxt in the X direction. The drive control unit 33 also has an encoder frequency division unit 332 that divides the output of the encoder of the X-axis motor Mx, and the output of the encoder divided by the encoder frequency division unit 332 is output to a camera trigger generation unit 341 of the imaging control unit 34. That is, the imaging control unit 34 has the camera trigger generation unit 341. This camera trigger generation unit 341 generates a camera trigger Tr based on the divided output of the encoder and outputs it to the camera control unit 42 of the component recognition camera 41.

[0036] That is, the component recognition camera 41 has a camera control unit 42. This camera control unit 42 has a trigger center estimation unit 421, a camera setting unit 422, and an exposure period correction unit 423. The trigger center estimation unit 421 estimates the center of a trigger interval, which is the time interval between two successive camera triggers Tr, based on the camera trigger Tr output from the camera trigger generation unit 341. The camera setting unit 422 holds parameters (e.g., the length of the exposure period Pe) required to set the exposure period Pe. The exposure period correction unit 423 sets the exposure period Pe based on the center of the trigger interval estimated by the trigger center estimation unit 421 and the parameters held by the camera setting unit 422.

[0037] As shown in FIG. 7, the component recognition camera 41 has the image sensor 411 as described above. The image sensor 411 detects light reflected by the component E in the imaging range V41 during the exposure period Pe, thereby detecting an image of one line (line image) extending in the Y direction. Furthermore, the component recognition camera 41 has an image generating unit 412 that synthesizes the line images detected by the image sensor 411 to generate an image of the entire component E (component recognition image Ir). The image generating unit 412 captures an image detected by the image sensor 411 each time the component E moves in the X direction by the width of the imaging range V41, thereby generating an image of the entire component E (component recognition image Ir). In the component recognition camera 41, the image sensor 411 and the image generating unit 412 form an imaging unit 413.

[0038] The component recognition image Ir generated by the image generation unit 412 is output to the camera control unit 42. The camera control unit 42 has a data processing circuit 426, an image memory unit 427, a correction circuit unit 428, and a transmission unit 429. The data processing circuit 426 writes the component recognition image Ir read out from the image generation unit 412 into the image memory unit 427. The correction circuit unit 428 performs correction processing such as distortion correction on the component recognition image Ir written into the image memory unit 427. Then, the transmission unit 429 transmits the component recognition image Ir after the correction processing to the receiving unit 348 of the imaging control unit 34. In other words, the imaging control unit 34 has the receiving unit 348 and the image data storage unit 349, and the component recognition image Ir received by the receiving unit 348 is stored in the image data storage unit 349.

[0039] 6, the trigger center estimation unit 421 starts counting using a counter that increments the count value over time (step S101). Then, the trigger center estimation unit 421 monitors whether a camera trigger Tr has been output from the camera trigger generation unit 341 (step S102).

[0040] When the trigger center estimation unit 421 confirms the output of the camera trigger Tr ("YES" in step S102), it resets the count value of the counter to zero (step S103). According to the example in Fig. 8, the count value of the counter is reset to zero in response to the output of the camera trigger Tra. This causes the count value of the counter to increase from zero as time passes from the output of the camera trigger Tra.

[0041] The trigger center estimation unit 421 continues to monitor the output of the camera trigger Tr from the camera trigger generation unit 341 (step S104). When the trigger center estimation unit 421 confirms the output of the camera trigger Tr ("YES" in step S104), it acquires the count value as the trigger interval It (step S105). That is, according to the example of FIG. 8, the count value of the counter at the time when the camera trigger Trb is output indicates the time interval between the camera trigger Tra and the camera trigger Trb that are output consecutively, that is, the trigger interval It. Therefore, the trigger center estimation unit 421 acquires the count value of the counter at the time when the camera trigger Trb is output as the trigger interval It. Furthermore, when the trigger center estimation unit 421 acquires this count value, it resets the count value of the counter to zero (step S106).

[0042] In step S107, the trigger center estimation unit 421 estimates the center of the trigger interval It based on the trigger interval It thus measured. According to the example of Fig. 8, for the camera triggers Tra, Trb, and Trc which are output continuously, the center Ct (center time) of the time interval (trigger interval) between the camera triggers Trb and Trc is estimated based on the trigger interval It between the camera triggers Tra and Trb. Specifically, the time when half the period (It / 2) of the trigger interval It has elapsed from the output time of the camera trigger Trb is estimated as the center Ct. The center Ct of the trigger interval It thus estimated is output from the trigger center estimation unit 421 to the exposure period correction unit 423.

[0043] In step S108, the trigger center estimation unit 421 sets the exposure period Pe so that the center Ce (center time) of the exposure period Pe coincides with the center Ct (center time) of the trigger interval It. Specifically, a time earlier than the center Ct by a period H that is half the length of the exposure period Pe stored in the camera setting unit 422 is set as the start time ts of the exposure period Pe, and a time later than the center Ct by the period H is set as the end time te of the exposure period Pe.

[0044] In step S109, the imaging unit 413 exposes the image sensor 411 during the exposure period Pe thus set. As a result, light reflected by the part E in the imaging range V41 during the exposure period Pe is detected by the image sensor 411. This control is repeatedly executed until the entire part E is imaged.

[0045] 6, the exposure period Pe is set at the center of the trigger interval It in both cases where the part E is moved in the first direction X1 and where the part E is moved in the second direction X2, and is not biased with respect to the trigger interval It. As a result, the position on the part E of the light (exposure reflected light) reflected by the part E in the imaging range V41 and used to expose the image sensor 411 is the same in both cases where the part E is moved in the first direction X1 and where the part E is moved in the second direction X2.

[0046] In the first example of the exposure control described above, the center Ct of the trigger interval It, which is the time interval between the camera trigger Trb (first trigger) output first and the camera trigger Trc (second trigger) output after the camera trigger Trb, among the two camera triggers Trb and Trc output consecutively, is estimated (step S107), and the center Ce of the exposure period Pe is set based on the center Ct of the trigger interval It (step S108). This suppresses the bias of the exposure period Pe relative to the trigger interval It. Then, the illumination unit 43 is turned on during the illumination period Pi that includes the exposure period Pe and is longer than the exposure period Pe, that is, illumination is continuously applied to the component E during the exposure period Pe. As a result, it is possible to image the component E while suppressing the difference in illumination conditions due to the difference in the moving direction of the component E relative to the image sensor 411 (image sensor).

[0047] Furthermore, the camera trigger generation unit 341 (trigger output unit) outputs multiple camera triggers Tr in sequence during the period when the part E passes through the imaging range V41. In response to this, the exposure period correction unit 423 (exposure control unit) sets multiple exposure periods Pe in accordance with the multiple camera triggers Tr, and the illumination unit 43 is continuously lit during the illumination period Pi including the multiple exposure periods Pe. In this configuration, the illumination unit 43 is lit throughout the multiple exposure periods Pe that are respectively set for the multiple camera triggers Tr, and the part E can be imaged while being irradiated with stable illumination.

[0048] Furthermore, according to the above-described exposure control, the exposure period correction unit 423 maintains the relationship between the center Ct of the trigger interval It and the center Ce of the exposure period Pe (i.e., the relationship in which the centers Ct and Ce coincide) regardless of changes in the length of the exposure period Pe. With this configuration, even if the length of the exposure period Pe changes, it is possible to image the component E while suppressing differences in illumination conditions caused by differences in the moving direction of the component E relative to the image sensor 411.

[0049] Furthermore, the exposure period correction unit 423 estimates the center Ct of the trigger interval It between the camera triggers Trb and Trc based on the time interval between the camera trigger Tra (third trigger) outputted before the camera trigger Trb (first trigger) and the camera trigger Trb (step S107). In this configuration, the center of the trigger interval It between the two camera triggers Trb and Trc sandwiching the exposure period Pe can be appropriately set based on the two camera triggers Tra and Trb outputted in succession immediately before the exposure period Pe.

[0050] Moreover, the exposure period correction unit 423 sets the exposure period Pe so that the center Ct of the trigger interval It and the center Ce of the exposure period Pe coincide with each other (step S108). With this configuration, it becomes possible to image the part E under substantially the same illumination conditions regardless of the difference in the moving direction of the part E relative to the image sensor 411.

[0051] Fig. 10 is a flowchart showing a second example of exposure control, and Fig. 11 is a block diagram showing an electrical configuration for executing the flowchart of Fig. 10. The second example of Fig. 10 differs from the first example of Fig. 6 in that the speed of the part E is used to estimate the center Ct of the trigger interval It, instead of the count value of the counter.

[0052] 11, the imaging control unit 34 has a command transmitting / receiving unit 342. The command transmitting / receiving unit 342 acquires speed information related to the speed (m / s) of the part E. This speed information may be, for example, the actual speed Vxe of the part E calculated from the encoder output of the X-axis motor Mx, or may be a speed command value Vxt. Furthermore, the command transmitting / receiving unit 342 has an imaging scale (m) indicating the width of the imaging range V41 in the X direction. The speed information and the imaging scale are output from the command transmitting / receiving unit 342 to the trigger center estimation unit 421.

[0053] 10, the trigger center estimation unit 421 checks the speed (m / s) indicated by the speed information. In step S202, the trigger center estimation unit 421 divides the imaging scale (m) by the speed (m / s) to calculate a trigger interval It, which is the time interval of the camera trigger Tr, and divides the trigger interval It by 2 to estimate the center Ct (center time) of the trigger interval It.

[0054] In step S203, the trigger center estimation unit 421 sets the exposure period Pe so that the center Ce (center time) of the exposure period Pe coincides with the center Ct (center time) of the trigger interval It. Specifically, a time earlier than the center Ct by a period H that is half the length of the exposure period Pe stored in the camera setting unit 422 is set as the start time ts of the exposure period Pe, and a time later than the center Ct by the period H is set as the end time te of the exposure period Pe.

[0055] Then, when the trigger center estimation unit 421 outputs a camera trigger Tr, the image sensor 411 is exposed in the exposure period Pe corresponding to the camera trigger Tr. That is, exposure is performed in the exposure period Pe set as described above for the center Ct of the trigger interval It between the camera trigger Tr and the camera trigger Tr next to the camera trigger Tr. As a result, light reflected by the part E in the imaging range V41 during the exposure period Pe is detected by the image sensor 411. This control is repeatedly performed until the entire part E is imaged.

[0056] In the second example of exposure control described above, the center Ct of the trigger interval It, which is the time interval between the camera trigger Tr output first and the camera trigger Tr output after the camera trigger Trb among two camera triggers Tr output in succession, is estimated (step S202), and the center Ce of the exposure period Pe is set based on the center Ct of the trigger interval It (step S203). This suppresses the bias of the exposure period Pe relative to the trigger interval It. Then, the illumination unit 43 is turned on during the illumination period Pi that includes the exposure period Pe and is longer than the exposure period Pe, that is, illumination is continuously applied to the component E during the exposure period Pe. As a result, it is possible to image the component E while suppressing the difference in illumination conditions due to the difference in the moving direction of the component E relative to the image sensor 411 (image sensor).

[0057] Furthermore, the trigger center estimation unit 421 (exposure control unit) estimates the center Ct of the trigger interval It between two consecutive camera triggers Tr (first trigger, second trigger) based on the relative moving speed of the part E with respect to the imaging range V41. With this configuration, it is possible to appropriately set the center Ct of the trigger interval It between the two camera triggers Tr sandwiching the exposure period Pe based on the moving speed of the part E.

[0058] As described above, in this embodiment, the component mounter 2 corresponds to an example of a "component mounter" of the present invention, the camera trigger generation unit 341 corresponds to an example of a "trigger output unit" of the present invention, the component recognition camera 41 corresponds to an example of a "camera" of the present invention, the image sensor 411 corresponds to an example of an "imaging element" of the present invention, the exposure period correction unit 423 corresponds to an example of an "exposure control unit" of the present invention, the illumination unit 43 corresponds to an example of an "illumination unit" of the present invention, the X-axis motor Mx corresponds to an example of a "component moving unit" of the present invention, the exposure period Pe corresponds to an example of an "exposure period" of the present invention, the camera trigger Tr corresponds to an example of a "trigger" of the present invention, and the imaging range V41 corresponds to an example of an "imaging range" of the present invention.

[0059] The present invention is not limited to the above embodiment, and various modifications can be made to the above without departing from the spirit of the present invention. For example, the width of the image sensor 411 as a line sensor may be one pixel or multiple pixels.

[0060] In addition, the image sensor 411 is not limited to a line sensor, and may be an area sensor. By setting a line-shaped ROI extending in the Y direction on the area sensor, the component E can be imaged in the same manner as described above.

[0061] Furthermore, the specific method of moving the component E relative to the imaging range V41 of the component recognition camera 41 is not limited to the above example. Therefore, the component E may be moved relative to the imaging range V41 by moving the component recognition camera 41 in the X direction. [Explanation of symbols]

[0062] 2. Component mounting machine 341...Camera trigger generation unit (trigger output unit) 41…Part recognition camera (camera) 411...Image sensor (imaging element) 423...Exposure period correction unit (exposure control unit) 43…Lighting section Mx...X-axis motor (parts moving part) Pe: Exposure period Tr...Camera trigger (trigger) V41…Image range

Claims

1. A camera having an imaging element for imaging an imaging range extending in a line shape; a part moving unit that moves a part relatively to the imaging range; an illumination unit that illuminates the imaging range by being turned on; a trigger output unit that outputs a trigger in response to the movement of the part by the part moving unit; an exposure control unit that causes the camera to expose the image sensor during an exposure period corresponding to the output of the trigger by the trigger output unit; Equipped with the illumination unit is turned on during a lighting period that includes the exposure period and is longer than the exposure period, The exposure control unit estimates the center of a trigger interval, which is the time interval between a first trigger that is output first and a second trigger that is output after the first trigger, of two triggers that are output in succession, and sets the center of the exposure period based on the center of the trigger interval.

2. the trigger output unit sequentially outputs a plurality of triggers during a period in which the component passes through the imaging range; the exposure control unit sets a plurality of exposure periods in response to a plurality of triggers; The component mounter according to claim 1 , wherein the illumination unit is continuously lit during the lighting period that includes the plurality of exposure periods.

3. The mounter according to claim 1 , wherein the exposure control unit maintains a relationship between a center of the trigger interval and a center of the exposure period regardless of a change in the length of the exposure period.

4. 2. The component mounter according to claim 1, wherein the exposure control unit estimates a center of the trigger interval between the first trigger and the second trigger based on a time interval between the first trigger and a third trigger that is output consecutively to the first trigger and before the first trigger.

5. The component mounter according to claim 1 , wherein the exposure control unit estimates a center of the trigger interval between the first trigger and the second trigger based on a relative moving speed of the component with respect to the imaging range.

6. 6. The mounter according to claim 1, wherein the exposure control unit sets the exposure period so that a center of the trigger interval coincides with a center of the exposure period.

7. a step of moving a part relative to an imaging range of a camera having an imaging element for imaging the imaging range extended in a line shape; turning on an illumination unit to irradiate the imaging range with illumination from the illumination unit; outputting a trigger in response to movement of the part relative to the imaging range; setting an exposure period in response to the trigger; causing the camera to expose the image sensor during the exposure period; Equipped with the illumination unit is turned on during a lighting period that includes the exposure period and is longer than the exposure period, In the step of setting the exposure period, a center of a trigger interval, which is the time interval between a first trigger that is output first and a second trigger that is output after the first trigger, is estimated, and the center of the exposure period is set based on the center of the trigger interval.

Images