JP2013222740A - Visual inspection device and visual inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual inspection device and a visual inspection method for always securing inspection accuracy to guarantee inspection quality.SOLUTION: In configuration for executing calibration processing for picking up a calibration jig by imaging means, and creating calibration data based on a measurement value for calibration extracted from image information acquired by imaging to be stored by a calibration processing execution part, a screen of an inspection before start-up for notifying that the calibration processing is executed is displayed prior to display of a production start screen, and a screen of an inspection before start-up for notifying that the calibration processing is executed is further displayed prior to display of a production end screen in stop of a visual inspection device. Thus, execution omission of the calibration processing resulting from human errors such as erroneous memory of an operator is certainly prevented, and inspection accuracy of the visual inspection device is secured to guarantee inspection quality.

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method for performing a predetermined inspection based on image information obtained by imaging an inspection object placed on an electronic component mounting line.

  A component mounting line for manufacturing a mounting substrate by mounting components on a substrate is configured by connecting a plurality of devices such as a solder printing device, a component mounting device, and a reflow device. The mounted and mounted substrate is carried into a reflow apparatus and heated, whereby the solder is melted and solidified to perform solder bonding. In such a component mounting process, an appearance inspection is performed for each process in order to confirm whether the solder printing state, the component mounting state, and the final component bonding state are correct. In this visual inspection, based on image information obtained by imaging the substrate after each process, inspection quantities and shapes such as dimensions and area of the inspection object are extracted, and the solder printing state, component mounting state, component An inspection is performed to determine whether the joining state is correct. As an appearance inspection apparatus that performs such an inspection, an apparatus having a calibration function of an optical system that images a substrate is generally used (see, for example, Patent Document 1). In the prior art shown in this patent document example, in appearance inspection using color image processing, predetermined calibration processing is performed based on image data obtained by imaging a calibration plate for brightness adjustment provided in the substrate positioning table. Like to do.

JP 2001-249084 A

  Along with the advancement of reliability required for electronic equipment, the reliability of inspection results required for visual inspection equipment has also become higher than that of conventional technologies, and it has become necessary to always ensure inspection accuracy. ing. However, since the calibration work for the inspection function is laborious and time-consuming to mount and calibrate a calibration jig prepared for each measurement item, precise calibration work is frequently performed in daily production activities. It's not practical to run on. For this reason, the inspection accuracy of visual inspection equipment is not always guaranteed, and even if an inspection mistake that identifies a defective product as a non-defective product is discovered in a later process, it is necessary to investigate the cause retroactively. It was in fact that there was no clear judgment as to whether or not As described above, in the prior art, there is a problem that it is difficult to always ensure the inspection accuracy of the appearance inspection apparatus, and the inspection quality is not always guaranteed.

  Therefore, an object of the present invention is to provide an appearance inspection apparatus and an appearance inspection method capable of always ensuring inspection accuracy and ensuring inspection quality.

  An appearance inspection apparatus according to the present invention is arranged on an electronic component mounting line for mounting an electronic component on a substrate to manufacture a mounting substrate, and the appearance inspection of an inspection object is performed based on image information acquired by imaging the substrate with an imaging unit. An inspection processing unit that performs a predetermined inspection determination process on the inspection item of the appearance inspection based on the measurement value extracted from the image information, and a calibration jig by the imaging unit. A calibration process execution unit that executes calibration processing for storing calibration data created based on a measurement value for calibration extracted from image information acquired by imaging and the calibration process performed by the calibration process execution unit A calibration execution control unit that controls an execution mode including execution timing based on a preset calibration execution pattern.

  The appearance inspection method of the present invention is based on image information obtained by imaging an image of the substrate by an imaging means by an appearance inspection device arranged on an electronic component mounting line for manufacturing the mounting substrate by mounting the electronic component on the substrate. An appearance inspection method for performing an appearance inspection of an inspection object, wherein an inspection processing step executes a predetermined inspection determination process for an inspection item of the appearance inspection based on a measurement value extracted from the image information, The calibration processing execution unit executes a calibration process in which a calibration jig is imaged by the imaging unit, and calibration data is created and stored based on a calibration measurement value extracted from image information acquired by the imaging. A calibration process execution step and an execution mode including a calibration process execution timing by the calibration process execution unit are performed based on a preset calibration execution pattern. And a calibration process execution control step of controlling the control unit.

  According to the present invention, a calibration process is performed by imaging a calibration jig by an imaging unit and creating and storing calibration data based on a calibration measurement value extracted from image information acquired by imaging. In the configuration executed by the control unit, the execution mode including the execution timing of the calibration process by the calibration process execution unit is controlled based on a preset calibration execution pattern, resulting in human error such as a memory difference of the operator. Forgetting to execute the calibration process can be surely prevented, and the inspection accuracy of the appearance inspection apparatus can be ensured to ensure the inspection quality.

Structure explanatory drawing of the electronic component mounting system of one embodiment of this invention Structure explanatory drawing of the screen printing apparatus used for the electronic component mounting system of one embodiment of this invention Structure explanatory drawing of the test | inspection / mounting apparatus used for the electronic component mounting system of one embodiment of this invention Configuration explanatory diagram of a calibration jig (first calibration jig) used in an appearance inspection apparatus according to an embodiment of the present invention Explanatory drawing of the individual calibration block with which the jig | tool for a calibration used for the external appearance inspection apparatus of one embodiment of this invention is attached. Configuration explanatory diagram of a calibration jig (second calibration jig) used in the appearance inspection apparatus of one embodiment of the present invention The block diagram which shows the structure of the control system of the electronic component mounting system of one embodiment of this invention Explanatory drawing of the data table for a calibration used for the external appearance inspection apparatus of one embodiment of this invention The flowchart which shows the calibration method in the external appearance inspection by the external appearance inspection apparatus of one embodiment of this invention Process explanatory drawing of the calibration method in the external appearance inspection by the external appearance inspection apparatus of one embodiment of the present invention The flowchart which shows the calibration process before and after work in the visual inspection method of one embodiment of this invention Explanatory drawing of the display screen displayed in the calibration process before the start of work in the appearance inspection method of one embodiment of the present invention The flowchart which shows the initial calibration process and time-dependent calibration process in the external appearance inspection method of one embodiment of this invention Process explanatory drawing of the initial calibration process and time-dependent calibration process in the appearance inspection method of one embodiment of the present invention The flowchart which shows the external appearance inspection method by the some external appearance inspection apparatus of one embodiment of this invention

  Next, embodiments of the present invention will be described with reference to the drawings. First, an electronic component mounting system 1 that manufactures a mounting board by mounting electronic components on a board will be described with reference to FIG. In FIG. 1, an electronic component mounting system 1 includes a printing apparatus M1, an inspection / mounting apparatus M2, an electronic component mounting apparatus M3, M4, an inspection / mounting apparatus M5, a board delivery apparatus M6, and a reflow apparatus M7. Mainly an electronic component mounting line connected in the (X direction). Each device constituting the electronic component mounting line is connected by the communication network 2 and controlled by the host device 3 having the function of a management computer. Thereby, transmission of a control command from the host system and signal exchange between the devices are performed.

  The printing apparatus M1 receives the substrate 4 supplied from the upstream substrate supply device (not shown) (arrow a), and solders for joining the components on the component connection electrode 4a (see FIG. 10). Paste S is screen printed. The substrate 4 after screen printing is carried into the downstream inspection / mounting apparatus M2 (arrow b). The inspection / mounting device M2, the electronic component mounting devices M3, M4, and the inspection / mounting device M5 are all provided on both sides of the substrate transfer mechanism 16 (see FIG. 3) for transferring the substrate 4 in the substrate transfer direction. It has a configuration in which a work operation mechanism such as a mechanism is arranged.

  The substrate transport mechanism 16 is composed of a pair of transport rails having a conveyor function, and the transport rail on one side is freely movable in the Y direction (arrow d). Accordingly, the conveyance width between the conveyance rails can be adjusted according to the substrate 4 to be targeted, and a first calibration jig 31 (see FIG. 4) described later is placed in the inspection / mounting apparatuses M2 and M5. It can be brought in.

  The inspection / mounting apparatus M2 includes a print inspection apparatus M2A and an electronic component mounting apparatus M2B. The print inspection apparatus M2A inspects the solder printing state on the printed circuit board 4 after printing. In this solder printing inspection, the position of the solder part formed on the substrate 4 is also measured, and each electronic device on the downstream side is used as solder position data for position correction during the component mounting operation by the downstream electronic component mounting apparatus. Feed forward to the component mounting apparatus.

  The electronic component mounting apparatus M2B mounts the electronic component 39 (see FIG. 10) on the substrate 4 after the solder printing inspection. The electronic component mounting apparatuses M3 and M4 include two electronic component mounting apparatuses M3A and M3B and electronic component mounting apparatuses M4A and M4B that can perform work operations independently of each other. The electronic components 39 are sequentially mounted.

  The inspection / mounting device M5 includes a mounting inspection device M5A and an electronic component mounting device M5B. The electronic component mounting device M5B mounts the electronic component 39 on the substrate 4, and the mounting inspection device M5A mounts each electronic component on the upstream side. The component mounting state is optically inspected for the substrate 4 after the component mounting operation by the apparatus is completed. The inspected substrate 4 is carried into the reflow device M7 via the substrate delivery device M6 (arrow c), and the solder is melted and solidified by heating here, and the electronic component 39 is soldered to the substrate 4.

  Next, the structure of the printing apparatus M1 will be described with reference to FIG. In FIG. 2, a substrate positioning portion 12 is disposed on the upper surface of the base 5. The substrate positioning unit 12 is a moving table provided with drive mechanisms in the X, Y, Z, and θ directions. The substrate positioning unit 12 is provided with a substrate transfer mechanism 6 including two transfer rails. By driving the substrate positioning unit 12, the substrate 4 carried in by the substrate transport mechanism 6 is received by the substrate lower receiving unit 13, and the substrate 4 positioned in the horizontal plane with respect to the screen mask 11 is the screen mask. 11 is in contact with the lower surface.

  Above the screen mask 11, a squeegee mechanism configured to reciprocate the squeegee head 9 held by the X-axis arm 8 in the Y direction by the Y-axis table 7 is disposed. The squeegee head 9 is provided with a pair of squeegees 10 that can be moved up and down, and screens according to the printing pattern of the substrate 4 by a squeegeeing operation of sliding the squeegee 10 on a screen mask 11 supplied with paste-like solder. Solder is printed on the substrate 4 through the pattern holes formed in the mask 11. The above-described squeezing mechanism and substrate positioning unit 12 constitute a screen printing mechanism 42 (see FIG. 7) that prints solder on the substrate 4.

  Next, the structure of the inspection / mounting apparatuses M2 and M5 will be described with reference to FIG. The electronic component mounting apparatuses M3A, M3B, M4A, and M4B of the electronic component mounting apparatuses M3 and M4 have the same configuration as the electronic component mounting apparatuses M2B and M5B shown in FIG. In FIG. 3, a substrate transfer mechanism 16 having two transfer rails is disposed in the X direction at the center of the base 15. The substrate transport mechanism 16 transports the substrate 4 loaded from the upstream device to the downstream side, and positions and holds the substrate 4 at a work position in the device. Then, a predetermined work operation is executed by the print inspection apparatus M2A, the electronic component mounting apparatus M2B, the mounting inspection apparatus M5A, and the electronic component mounting apparatus M5B with respect to the substrate 4 positioned and held by the respective substrate transport mechanisms 16.

  The electronic component mounting apparatuses M2B and M5B are provided with a component supply unit 17, and the component supply unit 17 is provided with a carriage 29 on which a plurality of tape feeders 18 are mounted in parallel. The tape feeder 18 supplies the electronic component to a pickup position by the component mounting portion described below by pulling out and pitch-feeding the carrier tape holding the electronic component from the tape supply reel 30 set on the carriage 29.

  A Y-axis moving table 19 provided with a linear motion mechanism using a linear motor is disposed in the Y direction at one end of the base 15 in the X direction. Similarly, X-axis movement tables 20A and 20B each having a linear motion mechanism using a linear motor are mounted on the Y-axis movement table 19 so as to extend in the X direction and be movable in the Y direction. The X-axis movement tables 20A and 20B correspond to the printing inspection apparatus M2A, the electronic component mounting apparatus M2B, the mounting inspection apparatus M5A, and the electronic component mounting apparatus M5B, respectively.

  A mounting head 25 including a plurality of unit mounting heads 26 is mounted on the X-axis moving table 20B so as to be movable in the X direction. Further, the X-axis moving table 20B is integrated with the mounting head 25 on the lower surface side. A board imaging unit 27 is provided. An inspection head 21 having a three-dimensional sensor 22 is mounted on the X-axis movement table 20A so as to be movable in the X direction. A cart 23 incorporating an inspection processing unit 24 is attached to the appearance inspection apparatuses M2A and M5A. Further, a second calibration jig 32 is fixedly disposed within the movement range of the three-dimensional sensor 22 in the substrate transport mechanism 16 on one side. As will be described later, the second calibration jig 32 is provided in order to appropriately correct an error caused by a change over time when the apparatus operation is continuously executed in the production process.

  The operation of the electronic component mounting apparatuses M2B and M5B will be described. By driving the Y-axis moving table 19 and the X-axis moving table 20B, the mounting head 25 moves horizontally in the X direction and the Y direction, and thereby the component is absorbed by the suction nozzle 26a mounted on the lower end of the unit mounting head 26. The electronic component is taken out from the tape feeder 18 of the supply unit 17, and the electronic component is mounted on the substrate 4 positioned and held by the substrate transport mechanism 16. Therefore, the Y-axis moving table 19, the X-axis moving table 20 B, and the mounting head 25 take out electronic components from the component supply unit 17 by the mounting head 25 and transfer them to the mounting position of the substrate 4 that is positioned and held by the substrate transport mechanism 16. The component mounting mechanism 54 (refer FIG. 7) to mount is comprised. By moving the substrate imaging unit 27 integrally with the mounting head 25, the substrate imaging unit 27 moves above the substrate 4 and images the substrate 4. And the recognition mark provided in the board | substrate 4 and the component mounting position are recognized by recognizing the image acquired by imaging.

  A component imaging unit 28 is disposed on the movement path of the mounting head 25 between the component supply unit 17 and the substrate transport mechanism 16. The mounting head 25 holding the electronic component by the suction nozzle 26 a moves in the X direction above the component imaging unit 28, thereby imaging the electronic component held by the mounting head 25 by the component imaging unit 28. And the positional information which shows the position shift from the normal position of an electronic component is acquired by recognizing the image acquired by imaging. In the component mounting operation on the board 4 by the component mounting mechanism 54, the position correction of the mounting position is performed based on this position information.

  Operations of the print inspection apparatus M2A and the mounting inspection apparatus M5A will be described. By driving the Y-axis movement table 19 and the X-axis movement table 20A, the inspection head 21 moves horizontally in the X direction and the Y direction. As a result, the substrate 4 that is operated in the pre-process apparatus and is positioned and held by the substrate transport mechanism 16 is imaged by the three-dimensional sensor 22 that is a three-dimensional imaging unit, and a three-dimensional image of the substrate 4 is acquired. In the appearance inspection, a predetermined inspection determination process is performed based on a plurality of measurement values extracted from the image information of the three-dimensional image corresponding to the inspection item.

  The three-dimensional sensor 22 is configured to receive reflected light, which is irradiated from a light source unit such as an LED and reflected from the inspection target position of the imaging target, by a PSD (position detection element). Then, by scanning the imaging light emitted from the light source unit within the imaging range of the imaging target, the reflected light from each imaging target position in the imaging range is received, and thereby a three-dimensional recognition image for inspection is obtained. To be acquired. Then, from the image information of the three-dimensional recognition image, a plurality of measurement values for the inspection determination process, that is, luminance information indicating the amount of light incident on the three-dimensional sensor 22, the horizontal direction and the height direction of the inspection target position. Three-dimensional position information indicating the position is acquired.

  The Y-axis movement table 19, the X-axis movement table 20A, and the inspection head 21 constitute an inspection mechanism 45 (see FIG. 7) that images the substrate 4 after the work is performed in the previous process for a predetermined inspection. Then, the three-dimensional recognition image acquired by the inspection head 21 is processed by an inspection processing unit 46 (see FIG. 7) built in the inspection processing unit 24, whereby an inspection corresponding to a predetermined purpose is performed. That is, in the printing inspection apparatus M2A, the solder printing state on the substrate 4 on which the solder is printed by the printing apparatus M1 of the pre-process apparatus is inspected. Therefore, the print inspection apparatus M2A is a print inspection unit that inspects the solder printing state on the substrate 4 on which the solder is printed by the solder printing unit. The mounting inspection device M5A is a mounting inspection unit that inspects the component mounting state on the substrate 4 on which the electronic components are mounted by the electronic component mounting devices M2B to M5B.

  Therefore, in the electronic component mounting system 1 having the above-described configuration, the print inspection apparatus M2A and the mounting inspection apparatus M5A are arranged on an electronic component mounting line that mounts electronic components on the substrate 4 to manufacture the mounted substrate, and the substrate 4 is three-dimensionally arranged. This is an appearance inspection apparatus that performs an appearance inspection of an inspection object based on image information obtained by imaging with a three-dimensional sensor 22 that is an imaging means. Here, as the configuration of the inspection mechanism 45, a configuration example is shown in which the inspection head 21 is moved relative to the substrate 4 that is positioned and fixed to the substrate transport mechanism. However, the substrate 4 is attached to the inspection head 21 that is fixedly arranged. A configuration for relative movement may be used.

  Next, referring to FIG. 4, FIG. 5, and FIG. 6, in the print inspection apparatus M2A and the mounting inspection apparatus M5A (appearance inspection apparatus) configured as described above, a plurality of pieces extracted from the image information corresponding to the inspection items of the appearance inspection. A calibration jig used to calibrate the measurement value will be described. As described above, in the print inspection apparatus M2A and the mounting inspection apparatus M5A, the measurement value corresponding to the inspection item (from the three-dimensional image information acquired by imaging the substrate 4 to be inspected by the three-dimensional sensor 22) ( Here, a luminance value and a three-dimensional position measurement value) are extracted. At this time, the extracted measurement value cannot be directly subjected to the inspection process, and the measurement value as raw data needs to be converted into the measurement value for inspection determination according to the inspection item. For this reason, prior to the start of the operation of the appearance inspection apparatus, calibration processing for creating calibration data for use in conversion of measurement values is performed by imaging the calibration jig with the three-dimensional sensor 22. .

  In the present embodiment, as such a calibration jig, a first calibration jig prepared as a reference jig used at the time of execution of preset calibration processing, such as at the time of starting up the apparatus or during maintenance inspection, is used. In addition to 31, a second calibration jig 32 that is fixedly disposed in the apparatus is used together in order to correct a change with time during the operation of the apparatus during production.

  First, the configuration of the first calibration jig 31 will be described with reference to FIG. As shown in FIG. 4A, the first calibration jig 31 includes a rectangular jig holder 31a and four individual calibration blocks (luminance calibration block 33, horizontal position calibration block 34, height) having different shapes. The position calibration block 35 and the simulated part block 36) are detachably held in series. These individual calibration blocks are provided exclusively for individually calibrating a plurality of measurement values.

  As shown in FIG. 4B, a rectangular fitting recess 31b is continuously formed in the X direction on the upper surface of the jig holder 31a. The brightness calibration block 33, the horizontal position calibration block 34, the height position calibration block 35, and the simulated part block 36 are fitted into the fitting recess 31b, and the fastening screw member 31c is fastened to the fastening holes 33a, 34a, 35a, 36a (FIG. 5). These individual calibration blocks are detachably held on the jig holder 31a by being inserted into the jig holder 31a.

  When the calibration process is executed, the first calibration jig 31 is automatically carried into the inspection / mounting apparatus M2 and the inspection / mounting apparatus M5 by the substrate transfer mechanism 16. That is, in the state where the distance between the two transport guides is matched with the width dimension of the jig holder 31a by the transport width adjusting function of the substrate transport mechanism 16, as shown in FIG. By transporting the tool 31 by the substrate transport mechanism 16 in the inspection / mounting apparatus M2 and the inspection / mounting apparatus M5, the first calibration jig 31 is held at a predetermined calibration work position. That is, the first calibration jig 31 includes a jig holder 31a that detachably holds a plurality of individual calibration blocks and can be transported by the substrate transport mechanism 16 of the inspection / mounting apparatus M2 and the inspection / mounting apparatus M5. It has a configuration.

  Next, the structure and function of these individual calibration blocks will be described with reference to FIG. The luminance calibration block 33, the horizontal position calibration block 34, the height position calibration block 35, and the simulated part block 36 are all plate-like members having a substantially square plane shape, and jig holders 31a are provided at respective diagonal positions. Fastening holes 33a, 34a, 35a, and 36a are provided for fastening. The luminance calibration block 33, the horizontal position calibration block 34, the height position calibration block 35, and the simulated part block 36 have shapes and structures suitable for calibrating the measurement values extracted from the three-dimensional recognition image.

  First, the luminance calibration block 33 (luminance calibration unit) shown in FIG. 5A is a calibration block for calibrating the measurement value of the amount of reflected light as luminance information. For this purpose, the reference reflection surface 33b of the luminance calibration block 33 is set so that the light reflection characteristic becomes a predetermined characteristic that matches the calibration purpose by adjusting the surface roughness or selecting the surface treatment. A horizontal position calibration block 34 (horizontal position calibration unit) shown in FIG. 5B is a calibration block for calibrating position information in the horizontal direction in three-dimensional position recognition. For this purpose, on the upper surface 34b of the horizontal position calibration block 34, two sets of parallel marks 34x and 34y made of two fine linear grooves that are equidistantly spaced in parallel are formed in a cross-beam shape. In the horizontal position calibration block 34, the parallel marks 34x and 34y are reference lines fixed in the X direction and the Y direction, respectively, and the intersection P of the parallel marks 34x and 34y is a fixed reference point.

  A height position calibration block 35 (height position calibration unit) shown in FIG. 5C is a calibration block for calibrating position information in the height direction in three-dimensional position recognition. For this purpose, on the upper surface 35b of the height position calibration block 35, a plurality of height reference surfaces 35c with known height positions and a step Δh are formed with a predetermined position accuracy. Further, the simulated part block 36 shown in FIG. 5D is used to determine whether or not a normal determination result can be obtained by executing a test determination process combining luminance information and three-dimensional position information in a simulated manner. This is a simulated part block. Here, a simulated component plate 36d having convex portions 36e and groove portions 36f as a simulated component portion provided on the upper surface 36b in a lattice shape is exchangeably mounted by a holding frame 36c, and the electronic component to be inspected is arranged. According to the shape and size, it is possible to appropriately select the simulated component part formed on the upper surface of the simulated component plate 36d.

  Next, the configuration and function of the second calibration jig 32 will be described with reference to FIG. As shown in FIG. 6 (a), a second calibration jig 32 is provided at a portion of the upper surface of the substrate transport mechanism 16 on one side of the inspection / mounting apparatuses M2 and M5 that can be imaged by the three-dimensional sensor 22. Is arranged (see FIG. 3). As shown in FIG. 6B, the second calibration jig 32 has a luminance calibration member 38 disposed on the base portion 32a fixed to the substrate transport mechanism 16 so as to be movable up and down, and further on the upper surface 38b. The horizontal position calibration plate 37 is mounted. The brightness calibration member 38 can be finely adjusted in height position H with respect to the base portion 32a by the adjusting screw 38a and the height adjusting mechanism 38c.

  Here, the upper surface 38b is set so that the light reflection characteristic becomes a predetermined characteristic that matches the calibration purpose, similarly to the reference reflection surface 33b of the luminance calibration block 33 in the first calibration jig 31. By finely adjusting the height position H of the upper surface 38b, the upper surface 38b can be adjusted to a reference height for calibration of the height position. Therefore, the luminance information and the height position information can be calibrated by imaging the luminance calibration member 38 with the three-dimensional sensor 22. On the upper surface of the horizontal position calibration plate 37, a plurality of position reference lines 37a composed of line segments in the Y direction are formed at a predetermined interval d in the X direction.

  The horizontal position information in the X direction can be calibrated by imaging the horizontal position calibration plate 37 with the three-dimensional sensor 22 and detecting the position of the position reference line 37a. In other words, the luminance calibration member 38 having the above-described configuration includes at least the functions of the luminance calibration block 33 (luminance calibration unit) and the height position calibration block 35 (height position calibration unit) in the first calibration jig 31. It has become.

  Next, the configuration of the control system of the electronic component mounting system 1 will be described with reference to FIG. In FIG. 7, the host device 3 is connected via a communication network 2 to a printing device M1, an appearance inspection device (printing inspection device M2A, mounting inspection device M5A), electronic component mounting devices M2B, M5B, and electronic component mounting devices M3, M4, and a substrate. It is connected to the delivery device M6. The printing device M1, the appearance inspection device (printing inspection device M2A, mounting inspection device M5A), the electronic component mounting devices M2B, M5B, the electronic component mounting devices M3, M4, and the board delivery device M6 are respectively connected to the communication units 40, 43, 52, 55 and control units 41, 44, 53, and 56, and signals can be exchanged between the host device 3 and each device via the respective communication units.

  The printing apparatus M1 includes a screen printing mechanism 42. When the control unit 41 controls the screen printing mechanism 42, a screen printing operation for the substrate 4 is executed. The appearance inspection apparatus (print inspection apparatus M2A, mounting inspection apparatus M5A) includes an inspection mechanism 45, an inspection processing unit 46, a calibration processing execution unit 47, a calibration execution control unit 48, a data storage unit 49, a measured value conversion processing unit 50, and a display unit. 51, and the control unit 44 controls the inspection mechanism 45 and the inspection processing unit 46, whereby the following inspection processing is executed.

  That is, in the printing inspection apparatus M2A, the solder printing state is inspected for the substrate 4 on which screen printing has been performed by the printing apparatus M1, and the inspection result including the pass / fail judgment is output together with the defect position data indicating the defect position. . Further, in the mounting inspection apparatus M5A, the component mounting state is inspected for the board 4 on which the components are mounted by the electronic component mounting apparatuses M2B, M3, M4, and M5B. It is output together with the indicated defect position data. In this inspection, the inspection data 49a stored in the data storage unit 49 is referred to. The inspection data 49a includes work data indicating the normal printing position and mounting position on the inspection target board 4, inspection determination data (threshold data) for determining the quality of the detected misalignment state, and the like. Contains the data necessary to perform the inspection.

  The inspection processing unit 46 performs an appearance inspection based on measurement values such as luminance information and three-dimensional position information extracted from three-dimensional image information acquired by the three-dimensional sensor 22 of the inspection mechanism 45 imaging the substrate 4. A predetermined inspection determination process is executed for the inspection item. For example, the printed quantity or printing position deviation of the solder printed on the electrode 4a in the substrate 4 and the presence or absence of the electronic component 39 mounted on the board 4 or the positional deviation are subject to inspection, and pass / fail judgment is made.

  The calibration processing execution unit 47 images the first calibration jig 31 or the second calibration jig 32 by the three-dimensional sensor 22, and based on the calibration measurement value extracted from the image information acquired by the imaging. Calibration data 49b is created and stored in the data storage unit 49. In the present embodiment, calibration data 49b is created for each of luminance information, horizontal position information, and height position information, and stored in the data storage unit 49 in the form of a data table or numerical conversion calculation formula for converting numerical data. Remembered.

  Data processing for creating the calibration data 49b will be described with reference to FIG. As described above, the measurement value extracted from the three-dimensional image information obtained by imaging the inspection target with the three-dimensional sensor 22 cannot be used as it is for the inspection process, and is used as a measurement value for determination according to the inspection item. Need to convert. The three types of straight line graphs shown in FIG. 8 are conversion calibration data tables in which the measurement values (input) indicated on the horizontal axis correspond to the measurement values (output) for determination indicated on the vertical axis.

  First, FIG. 8A shows an (input-output) correlation line L1 obtained as a calibration processing result at the time of executing a predetermined reference calibration operation such as after completion of assembly of the apparatus or after completion of periodic maintenance. That is, the first calibration jig 31 is carried into the inspection / mounting apparatus M2 and the inspection / mounting apparatus M5, and the measured value I1 is extracted as raw data from the image information obtained by sequentially capturing the individual calibration blocks by the three-dimensional sensor 22. And input to the calibration processing execution unit 47. In the calibration process, a determination numerical value (measurement value O1) that is determined to be appropriate in the inspection determination in the same inspection process is determined as an output value corresponding to the input value (measurement value I1). A straight line that satisfies the numerical range is acquired as the target (input-output) correlation line L1. In the inspection process executed thereafter, the inspection determination process is performed using the determination numerical value (measurement value O1) obtained by converting the input measurement value using the (input-output) correlation line L1.

  FIG. 8B shows the change in the correlation between the input and the output in the state in which the time-dependent change occurs in the operation of the inspection mechanism 45 of the appearance inspection apparatus in the process in which the electronic component mounting system continues to operate. Even if there is no change in the state of the inspection target part itself due to the change in the light receiving state of the reflected light in the three-dimensional sensor 22 due to the influence of the thermal displacement of the movable part constituting the inspection mechanism 45 and the change in the illumination state. Variations may occur in the measurement values input to the inspection processing unit 46. That is, although the measurement value I1 is supposed to be input, a measurement value I2 that is different from I1 is input due to a change over time. When this input value is converted into an output value using the (input-output) correlation line L1 obtained in FIG. 8A, a judgment numerical value (measured value O1) is supposed to be output. In this case, the measurement value O2 corresponding to the measurement value I2 is output, and an erroneous determination in which an original proper inspection determination result cannot be obtained occurs.

  FIG. 8C shows a correction process for the calibration data table that is executed in order to prevent such erroneous determination due to temporal variation. Here, even when the measurement value I2 is input, the correlation line is corrected so as to be converted into the measurement value O1 that should be output. That is, the corrected correlation line L2 obtained by translating the (input-output) correlation line L1 set in FIG. 8A so that the determination numerical value (measurement value O1) corresponds to the input value (measurement value I2). To correct. In the inspection process executed thereafter, the inspection determination process is performed using the determination numerical value obtained by converting the input measurement value using the correction correlation line L2.

  The calibration execution control unit 48 controls the execution mode including the execution timing of the calibration process by the calibration process execution unit 47 based on the calibration execution pattern 49 c that is preset and stored in the data storage unit 49. That is, the calibration execution pattern 49c is displayed on the display screen of the display unit 51 in association with the timing at which the calibration process execution unit 47 executes the calibration process, the selection of the calibration jig used for the calibration process, and the calibration process. The contents to be specified are defined in advance.

  For example, in the present embodiment, as the calibration execution pattern 49c, a pre-start inspection screen for notifying that the calibration process is executed is displayed prior to the display of the production start screen displayed on the display unit 51 when the appearance inspection apparatus is activated. A pre-work inspection pattern and a pre-work inspection pattern for displaying a post-work inspection screen for notifying that the calibration process is executed are stored prior to the display of the production end screen displayed when the appearance inspection apparatus is stopped.

  Further, in the present embodiment, the first calibration jig 31 prepared as a reference jig is used for calibration of the measurement value in the inspection process based on the measurement value extracted from the image information acquired by imaging. Based on an initial calibration process for creating a calibration data table and a measurement value extracted from image information acquired by imaging a second calibration jig for temporal correction arranged to correct temporal variation In addition, a combined calibration pattern is stored for executing the time-dependent calibration process for correcting the calibration data table in combination at a predetermined timing.

  The measurement value conversion processing unit 50 converts the measurement value for inspection extracted from the image information acquired by imaging the inspection object using the calibration data table stored as the calibration data 49b, and performs measurement for determination. Process to output as a value. The display unit 51 includes a display panel such as a liquid crystal panel, and displays a display screen for notification to the worker and operation by the worker. In the present embodiment, a display screen that prompts execution of calibration processing at the start of production / end of production is included.

  The electronic component mounting apparatuses M2B, M3, M4, and M5B include a component mounting mechanism 54, and the control unit 53 controls the component mounting mechanism 54 to mount the electronic component on the board 4 after solder printing. Work is performed. The board transfer device M6 includes a board transfer mechanism 57. When the control unit 56 controls the board transfer mechanism 57, a board transfer operation for transferring the board 4 after component mounting to the reflow apparatus M7 is executed.

  The appearance inspection apparatuses (print inspection apparatus M2A, mounting inspection apparatus M5A) in this electronic component mounting system are configured as described above, and are subsequently executed along with the appearance inspection method and the appearance inspection performed by the appearance inspection apparatus. A calibration method will be described. First, referring to FIG. 9 and FIG. 10, a calibration method in an appearance inspection that calibrates a plurality of measurement values extracted from image information obtained by imaging by a three-dimensional sensor 22 corresponding to an inspection item of an appearance inspection. explain.

  In FIG. 9, first, the first calibration jig 31 having the individual calibration block held by the jig holder 31a is prepared (jig preparation step) (ST1). That is, a luminance calibration block 33, a horizontal position calibration block 34, a height position calibration block 35, and a simulated part block 36 provided for individually calibrating a plurality of measurement values are converted into jigs shown in FIG. The first calibration jig 31 is configured by being held by the holder 31a. Next, as shown in FIG. 10A, the prepared first calibration jig 31 is transported by the substrate transport mechanism 16 and transported to the appearance inspection apparatus (a jig transporting step) (ST2). Next, as shown in FIG. 10B, the first calibration jig 31 is imaged by the three-dimensional sensor 22 to acquire image information for calibration (imaging process) (ST3).

  Thereafter, calibration data is created based on the measurement values extracted from the image information (ST4), and the created calibration data is stored as a data table in a predetermined data format (calibration data storage step) ( ST5). As a result, the calibration data table shown in FIG. 8A is stored in the data storage unit 49. Next, production by the electronic component mounting line is started (ST6).

  That is, as shown in FIG. 10C, in the printing apparatus M1, the solder paste S is printed on the electrode 4a formed on the substrate 4 by sliding the squeegee 10 on the screen mask 11. In the electronic component mounting apparatuses M2B, M3, M4, and M5B, the electronic component 39 is mounted by the unit mounting head 26 on the substrate 4 on which the solder paste S is printed on the electrode 4a. Then, the inspection process is executed for each substrate with respect to the substrate 4 in the production process (ST7).

  That is, as shown in FIG. 10D, in the print inspection apparatus M2A, the substrate 4 in a state where the solder paste S is printed on the electrode 4a is imaged by the three-dimensional sensor 22. In the mounting inspection apparatus M5A, the three-dimensional sensor 22 images the substrate 4 on which the electronic component 39 is mounted on the electrode 4a. And based on the measured value extracted from the image information acquired by these imaging, a predetermined test | inspection determination process is repeatedly performed for every board | substrate.

  In this way, as a calibration jig used for calibrating a plurality of measurement values extracted from image information corresponding to the inspection items of the appearance inspection, provided for calibrating a plurality of measurement values individually. By using the first calibration jig 31 configured to detachably hold a plurality of individual calibration blocks on a jig holder 31a that can be transported by the substrate transport mechanism 16 of the visual inspection apparatus, three-dimensional image information is obtained. Even when a plurality of types of calibration members prepared for each inspection item are required, such as when a plurality of inspection items are used, it is not necessary to replace the calibration member for each item each time. As a result, the labor and time required for the calibration work can be reduced, the calibration jig can be easily managed and used properly, and misuse can be effectively prevented. Therefore, productivity can be improved by reducing the work load of calibration work and the management load at the production site.

  In the above-described appearance inspection, a predetermined inspection determination process is executed by the inspection processing unit 46 for the inspection item of the appearance inspection based on the measurement value extracted from the image information acquired by the three-dimensional sensor 22 (inspection processing step). . Then, in order to correctly calibrate the measurement values used in the inspection determination process, the first calibration jig 31 or the second calibration jig 32 is imaged by the three-dimensional sensor 22 and extracted from the image information acquired by the imaging. The calibration process execution unit 47 executes a calibration process for creating the calibration data 49b based on the calibration measurement values and storing the calibration data 49b in the data storage unit 49 (calibration process execution step). In the present embodiment, as will be described below, the execution mode including the execution timing of the calibration process by the calibration process execution unit 47 is set in advance and is based on the calibration execution pattern 49c stored in the data storage unit 49. Then, it is controlled by the calibration execution control unit 48 (calibration process execution control step).

  As the calibration execution pattern 49c, the above-mentioned pre-start inspection pattern, pre-end inspection pattern, and combined calibration pattern are stored, and a specific example of calibration processing executed according to these calibration execution patterns will be described below. First, with reference to FIG. 11 and FIG. 12, the calibration process before start and before work in the appearance inspection method executed according to the check pattern before starting work and the check pattern after closing work will be described.

  In FIG. 11, after the appearance inspection apparatus is activated, a pre-start inspection screen is displayed prior to the production start screen display (ST11). That is, when starting each device on the electronic component mounting line to start production, a production start screen is displayed on each device in a predetermined display format. In the present embodiment, prior to the display of the production start screen displayed on the display screen 51a of the display unit 51 when the appearance inspection apparatus is started up, as shown in FIG. The screen 60 is displayed. The display frame 61 of the pre-start inspection screen 60 displays that “calibration processing is executed prior to the start of production”.

  Upon receiving this notification, the operator executes a predetermined pre-start calibration process (ST12), and confirms whether there is an abnormality in the calibration result (ST13). Here, if it is recognized that there is an abnormality in the calibration result, it is notified that there is an abnormality (ST14A), and if it is recognized that there is no abnormality, a normal production start screen is displayed (ST14B). Thereby, the production process for the substrate 4 is started.

  That is, in the production process, the substrate 4 is imaged by the three-dimensional sensor 22 to acquire image information for inspection (ST15), and a predetermined inspection determination process is executed based on the measurement value extracted from the acquired image information ( ST16). In the process of repeating this production process, it is determined whether or not the predetermined production number is completed (ST17). If the production number is completed, the process proceeds to preparation for the end of production. Here, in the present embodiment, prior to the display of the production end screen displayed on the display screen 51a of the display unit 51 at the end of production, as shown in FIG. 62 is displayed (ST18). The display frame 63 of the pre-work inspection screen 62 displays that “Calibration processing is executed prior to the end of production”. Upon receiving this notification, the operator executes a predetermined pre-work-time calibration process (ST19), after which a normal production end screen is displayed.

  In this way, a pre-start inspection screen for notifying that the calibration process is executed is displayed prior to the display of the production start screen, and further, the calibration process is executed prior to the display of the production end screen when the appearance inspection apparatus is stopped. By displaying the pre-start inspection screen for informing the user, it is possible to reliably prevent the user from forgetting to execute the calibration process due to human error such as a memory difference of the worker. Thereby, the inspection accuracy of the appearance inspection apparatus can be ensured and the inspection quality can be guaranteed.

  Next, an initial calibration process and a time-dependent calibration process in the appearance inspection method will be described with reference to FIGS. Here, the combined calibration pattern stored as the calibration execution pattern 49c, that is, the initial calibration process using the first calibration jig 31 and the temporal calibration process using the second calibration jig 32 are set in advance, respectively. The calibration process is executed according to the calibration pattern that is executed in combination at the predetermined timing.

  When the electronic component mounting line is activated, a production start screen is displayed on the appearance inspection apparatus (ST21). Next, the first calibration jig 31 is carried into the appearance inspection apparatus (ST22), and as shown in FIG. 14A, the first calibration jig 31 is imaged by the three-dimensional sensor 22 for calibration. Is acquired (ST23). Next, a calibration data table used for calibration of the measurement value is created based on the measurement value extracted from the acquired image information (initial calibration process) (ST24). That is, a data table indicated by the (input-output) correlation line L1 in the graph of FIG. 8A is created and stored as calibration data 49b in the data storage unit 49 (ST25).

  Thereafter, the production process for the substrate 4 is started. In the production process, as shown in FIG. 14B, the substrate 4 after solder printing in which the solder paste S is printed on the electrode 4a or the substrate 4 after mounting the electronic component 39 on the electrode 4a is three-dimensionally mounted. Image information for inspection is acquired by the sensor 22 and acquired (ST26). Then, based on the measurement value extracted from the acquired image information, a predetermined inspection determination process is executed (ST27).

  In the process of repeating this production process, the inspection head 21 is moved above the second calibration jig 32 at a predetermined interval, and the second calibration process is performed as shown in FIG. The tool 32 is imaged by the three-dimensional sensor 22 to acquire image information (ST28). Here, luminance information and height position information are acquired by imaging the upper surface 38b of the luminance calibration member 38, and horizontal position information in the X direction is acquired by imaging the horizontal position calibration plate 37 (FIG. 6). reference).

  Then, the calibration data table is corrected based on the measurement values extracted from the acquired image information (time-dependent calibration process) (ST29). That is, as shown in FIG. 8C, a corrected correlation line L2 is created by translating the (input-output) correlation line L1 by the change over time. As the predetermined interval for executing the time-dependent calibration process, the continuous operation time or the number of produced substrates can be used as appropriate. This imaging operation is performed using an idle time during which the inspection head 21 does not perform a work operation on the substrate 4.

  As described above, the initial calibration process using the first calibration jig 31 and the time-dependent calibration process using the second calibration jig 32 are executed in combination at predetermined timings, respectively. By using the calibration pattern, an effective calibration process can be performed for various factors that affect the inspection accuracy. That is, it is possible to effectively cope with accuracy errors and assembly errors of mechanical parts constituting the three-dimensional sensor 22 that is an imaging optical system by the initial calibration process. For error factors that change over time, such as temperature changes in the installation environment, such as relative position errors between the substrate and the three-dimensional sensor 22, the time calibration process is repeatedly performed at appropriate intervals, so that Variation in inspection accuracy over time can be prevented by a simple method.

  Next, an appearance inspection method when the inspection objects are of the same substrate type and these inspection objects are to be inspected by a plurality of appearance inspection apparatuses will be described with reference to FIG. Here, by using a common jig for a plurality of appearance inspection apparatuses as a calibration jig used in the calibration process, it is possible to use common inspection determination data in an inspection processing step executed by the plurality of appearance inspection apparatuses. It is possible.

  First, a single first calibration jig 31 that is commonly used for a plurality of visual inspection apparatuses is sequentially carried into each visual inspection apparatus (ST31), and the first calibration jig is carried out for each carried visual inspection apparatus. The tool 31 is imaged by the three-dimensional sensor 22 to acquire image information (ST32). Next, based on the calibration measurement values extracted from the acquired image information, the calibration processing execution unit 47 executes calibration processing for creating and storing calibration data used for calibration of the measurement values (calibration processing). Execution step) (ST33). The created calibration data is stored in the data storage unit 49 as a calibration data table unique to the appearance inspection apparatus (calibration data storage step) (ST34).

  Thereafter, the production process for the substrate 4 is started. In the production process, the board 4 after solder printing in which the solder paste S is printed on the electrode 4a or the board 4 on which the electronic component 39 is mounted on the electrode 4a is imaged by the three-dimensional sensor 22, and an inspection image is obtained. Information is acquired (ST35). Then, the measurement value for inspection extracted from the image information is converted by the calibration data table by the function of the measurement value conversion processing unit 50, and is output as the measurement value for determination (measurement value conversion processing step). In the inspection processing step, the output measurement value for determination is compared with the inspection determination data stored in the data storage unit 49 as the inspection data 49a, and inspection processing is executed. The inspection determination data used here is data that is commonly used for a plurality of appearance inspection apparatuses, and is always the same data even when the plurality of appearance inspection apparatuses have inherent inter-device errors. Can be used.

  Many factors that affect inspection accuracy include those that change over time depending on the elapsed time of use since the start of equipment operation. If the time is different, an error between devices may occur in measurement accuracy for inspection. In order to prevent the deterioration of inspection accuracy due to such an inter-device error, it is necessary in the prior art to prepare a plurality of types by separately setting inspection determination data such as different inspection threshold values according to the state of each device. .

  On the other hand, in the appearance inspection method shown in the present embodiment, calibration processing is performed by each appearance inspection apparatus using the single first calibration jig 31, and calibration data unique to each apparatus is created. This makes it possible to use common inspection determination data for a plurality of visual inspection apparatuses and reduce the data management load at the production site.

  In the above embodiment, the inspection / mounting apparatus M2 is provided with the print inspection apparatus M2A as the print inspection section and the electronic component mounting apparatus M2B as the component mounting section on both sides of the board conveyance mechanism provided on the common base. Also, the example in which the electronic component mounting system 1 is configured including the inspection / mounting device M5 provided with the mounting inspection device M5A as the mounting inspection unit and the electronic component mounting device M5B as the component mounting unit has been shown. Is not limited to such a configuration. For example, the present invention can be applied to a configuration in which a single device having the functions of the print inspection device M2A, the electronic component mounting devices M2B and M5B, and the mounting inspection device M5A is connected in series on the downstream side of the printing device M1.

  In the present embodiment, an example is shown in which a three-dimensional sensor that acquires three-dimensional image information using a position detection element is used as an imaging unit that acquires image information for appearance inspection. Is not limited to a three-dimensional sensor. That is, in an image recognition process for the purpose of appearance inspection, if the appearance inspection apparatus has a configuration that requires calibration processing for calibrating image information such as luminance information and position information, the appearance is determined using a two-dimensional area camera or the like. The present invention can be applied even when an inspection is performed.

  INDUSTRIAL APPLICABILITY The appearance inspection apparatus and the appearance inspection method of the present invention have an effect that inspection accuracy can be always ensured and inspection quality can be ensured, and an electronic component mounting field for manufacturing a mounting substrate by mounting electronic components on a substrate Is useful.

DESCRIPTION OF SYMBOLS 1 Electronic component mounting system 3 Host apparatus 4 Board | substrate 4a Electrode 16 Board | substrate conveyance mechanism 21 Inspection head 22 Three-dimensional sensor 24 Inspection processing unit 25 Mounting head 31 1st calibration jig 31a Jig holder 32 2nd calibration jig 33 Luminance calibration block 33b Reference reflecting surface 34 Horizontal position calibration block 34x, 34y Parallel mark 35 Height position calibration block 35c Height reference surface 36 Simulated component block 36d Simulated component plate 37 Horizontal position calibration plate 38 Luminance calibration member 38b Upper surface 39 Electronic Component P Reference point S Solder paste M1 Printing device M2, M5 Inspection / mounting device M2A Printing inspection device M5A Mounting inspection device M3, M4 Electronic component mounting device

Claims (7)

An appearance inspection apparatus that is disposed on an electronic component mounting line that mounts electronic components on a substrate and manufactures a mounting substrate, and performs an appearance inspection of an inspection object based on image information acquired by imaging the substrate by an imaging unit. ,
An inspection processing unit that performs a predetermined inspection determination process on the inspection item of the appearance inspection based on the measurement value extracted from the image information;
A calibration processing execution unit that performs calibration processing for capturing calibration data created based on measurement values for calibration extracted from image information acquired by imaging, imaging a calibration jig by the imaging unit;
An appearance inspection apparatus comprising: a calibration execution control unit that controls an execution mode including a calibration process execution timing by the calibration process execution unit based on a preset calibration execution pattern. A display screen is provided for notification to the worker and operation by the worker.
The calibration execution control unit displays a pre-start inspection screen for notifying that the calibration processing is executed prior to displaying the production start screen displayed on the display screen when the appearance inspection apparatus is started. The visual inspection apparatus according to claim 1.   Further, the calibration execution control unit displays a post-start inspection screen for notifying that the calibration processing is executed prior to displaying the production end screen displayed on the display screen when the appearance inspection apparatus is stopped. The appearance inspection apparatus according to claim 2, wherein: The imaging means is a three-dimensional imaging means for acquiring three-dimensional image information;
The plurality of measurement values extracted from the three-dimensional image information corresponding to the inspection item of the appearance inspection is a luminance that represents the amount of light reflected from the inspection target position of the inspection object incident on the three-dimensional imaging unit. Information, including three-dimensional position information indicating horizontal and height positions of the inspection target position of the inspection object,
The calibration jig includes a luminance calibration unit in which a light reflection characteristic is set to a predetermined characteristic in order to calibrate the luminance information,
A horizontal position calibration unit in which at least one reference point and at least two reference lines for calibrating the horizontal position information are formed with a predetermined position accuracy;
4. A height position calibration unit in which a plurality of height reference planes are formed with a predetermined position accuracy in order to calibrate the position information in the height direction. Visual inspection equipment. An appearance inspection apparatus arranged on an electronic component mounting line for mounting electronic components on a board to manufacture a mounting board performs an appearance inspection of an inspection object based on image information acquired by imaging the board with an imaging means. An appearance inspection method,
An inspection processing step in which a predetermined inspection determination process is executed by the inspection processing unit for the inspection item of the appearance inspection based on the measurement value extracted from the image information;
Calibration by which calibration processing is performed by imaging a calibration jig by the imaging means, and creating and storing calibration data based on measurement values for calibration extracted from image information acquired by imaging Processing execution process;
And a calibration process execution control step for controlling an execution mode including the execution timing of the calibration process by the calibration process execution unit based on a preset calibration execution pattern. . The visual inspection apparatus includes a display screen for notification to the operator and operation by the operator,
In the calibration process execution control step, a pre-start inspection screen for notifying that the calibration process is executed is displayed on the display screen prior to display of the production start screen when the appearance inspection apparatus is started. Item 5. The appearance inspection method according to Item 5.   Further, in the calibration process execution control step, a post-start inspection screen for notifying that the calibration process is executed is displayed prior to the display of the production end screen displayed on the display screen when the appearance inspection apparatus is stopped. The visual inspection method according to claim 6.

Images