Workpiece height measuring device and mounting board inspection device using the same

Abstract

This workpiece height measurement device comprises an imaging unit for capturing an image of a workpiece, a line light projection unit which has a projection optical axis at a prescribed angle of intersection with an imaging optical axis and is capable of radiating line light from a plurality of directions to the workpiece, a scan drive unit for causing the imaging unit and the line light projection unit to move to perform scanning of the workpiece, and a measurement unit for determining height data of the workpiece by an optical cutting method on the basis of images acquired by the scanning. The measurement unit causes the line light to be radiated to the workpiece from a prescribed irradiation direction to perform a first scan, determines whether there is a missing part in the workpiece height data, in the height data obtained on the basis of an image acquired by the first scan, and causes a second scan to be performed in which the irradiation direction of the line light is different from that of the first scan when a missing part is detected.

Description

[Technical field]

[0001] The present invention relates to a height measurement device for a workpiece such as an electronic component mounted on a board, and to a mounted board inspection device using the same. [Background technology]

[0002] For example, in a production line for component-mounted boards in which electronic components (workpieces) are mounted on a board, it is necessary to inspect whether the electronic components are mounted on the board as designed. By measuring the height of the component-mounted board, it is possible to detect mounting defects of electronic components, such as component floating, misalignment of mounting position, and missing mounting. The light-section method is known as a method for measuring the height of a workpiece without contact. In the light-section method, an image of a workpiece obliquely irradiated with a line light is captured, and the height of the workpiece is obtained from the captured image based on the principle of triangulation. Patent Document 1 discloses a three-dimensional shape measuring device for a workpiece using the light-section method. The device of Patent Document 1 includes a mechanism for rotating a light-section probe equipped with a line light source and an imaging camera.

[0003] When measuring the workpiece height, a scan is performed in which the line light source and the imaging camera are moved horizontally relative to the workpiece, and multiple images are captured. Height data is obtained from each image obtained by the scan, and the shape of the workpiece can be measured by combining these height data. Here, for example, when multiple workpieces are arranged at high density, or when a low workpiece is arranged adjacent to a high workpiece, the line light that should be irradiated to the target workpiece may be blocked by the adjacent workpiece. In this case, a problem occurs in which the height of the target workpiece cannot be accurately measured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-72197 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a work height measuring device that can accurately measure the height of a work regardless of the arrangement of the work, and a mounted board inspection device using the same.

[0006] A workpiece height measuring device according to one aspect of the present invention comprises an imaging unit having an imaging optical axis in a vertical direction and capturing an image of the workpiece; a line light projection unit having a projection optical axis having a predetermined intersection angle with the imaging optical axis and capable of irradiating the workpiece with line light from a plurality of orientations; a scan drive unit moving the imaging unit and the line light projection unit to scan the workpiece; and a measurement unit controlling the scan drive unit to perform the scan and determining height data of the workpiece by a light section method based on the image acquired by the scan, wherein the measurement unit performs a first scan by irradiating the line light onto the workpiece from a predetermined irradiation direction, and determines whether or not there are any missing portions in the height data of the workpiece in the height data obtained based on the image acquired in the first scan, and if any missing portions are detected, performs a second scan in which the irradiation direction of the line light is in a different orientation from that of the first scan.

[0007] A mounted board inspection apparatus according to another aspect of the present invention includes an inspection stage onto which a mounted board having components mounted thereon is carried in, and the above-described work height measuring device that measures the height of the components on the mounted board carried into the inspection stage as the work. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a mounting board production line in which a workpiece height measuring device according to the present invention is incorporated as an appearance inspection machine. [Diagram 2] 2(A) to (C) are schematic diagrams showing a part height measurement technique using the light-section method. [Diagram 3]3A and 3B are diagrams for explaining the drawbacks of component height measurement using the light-section method, and FIG. 3C is a diagram showing a solution to the drawbacks. [Figure 4] FIG. 4 is a perspective view showing a schematic hardware configuration of the visual inspection machine. [Diagram 5] FIG. 5 is a block diagram showing the electrical configuration of the appearance inspection machine. [Figure 6] 6(A) to 6(C) are perspective views showing a rotating state of a head equipped with a camera unit and a line light source. [Figure 7] FIG. 7 is a perspective view showing a head according to a modified example. [Figure 8] 8(A) to (D) are schematic diagrams for explaining component height measurement according to the first embodiment. [Figure 9] 9(A) to (D) are schematic diagrams for explaining component height measurement according to the first embodiment. [Figure 10] 10(A) to (D) are schematic diagrams for explaining component height measurement according to the second embodiment. [Figure 11] 11(A) to (C) are schematic diagrams for explaining component height measurement according to the second embodiment. [Figure 12] FIG. 12 is a flowchart showing a scan direction determination process in part height measurement according to the second embodiment. [Figure 13] 13(A) to (E) are schematic diagrams for explaining component height measurement according to the third embodiment. [Figure 14] 14A and 14B are schematic diagrams for explaining component height measurement according to the fourth embodiment. [Figure 15] 15(A) and (B) are schematic diagrams for explaining component height measurement according to the fourth embodiment. [Figure 16] FIG. 16 is a flowchart showing a scan area determination process in part height measurement according to the fourth embodiment. [Figure 17] 17(A) to (C) are schematic diagrams for explaining component height measurement according to the fifth embodiment. [Figure 18] 18(A) to (C) are schematic diagrams for explaining component height measurement according to the fifth embodiment. [Figure 19] FIG. 19 is a flowchart showing a process for determining a scanning direction for each component in component height measurement according to the fifth embodiment. [Figure 20] 20(A) to (C) are schematic diagrams for explaining component height measurement according to a modified example of the fifth embodiment. [Figure 21] FIG. 21 is a flowchart showing a process for determining a scanning direction for each component in component height measurement according to a modified example of the fifth embodiment. [Figure 22] 22(A) to (D) are schematic diagrams for explaining component height measurement according to the sixth embodiment. [Diagram 23] FIG. 23 is a flowchart showing the process of creating high-resolution component height data in component height measurement according to the sixth embodiment. [Figure 24] 24(A) and (B) are diagrams showing modified examples of scanning. [Diagram 25] FIG. 25 is a diagram showing a modified example of image data acquisition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The work height measuring device according to the present invention can be widely applied to measuring the shapes of workpieces such as various industrial products, semi-finished products, machine parts, electronic parts, food, agricultural products, etc. In the embodiment shown below, an example will be described in which height measurement is performed on a component mounted on a board as a workpiece. Here, an example will be shown in which the work height measuring device according to the present invention is applied to visual inspection of a board after components are mounted on the board in a production line for mounting boards.

[0010] [Mounted circuit board production line] 1 is a block diagram showing the configuration of a mounted board production line 1 for mounting electronic components on printed circuit boards. The mounted board production line 1 includes a printer 11, a print inspection machine 12, a component mounter 13, a reflow oven 14, and an appearance inspection machine 15 (work height measuring device / mounted board inspection device), which are arranged in this order from the upstream side to the downstream side in the board transport direction.

[0011] The printer 11 applies solder to the pads of the printed circuit board. For example, the printer 11 places a mask with openings for the solder application area on the printed circuit board, and applies cream solder through the mask. The print inspection machine 12 inspects whether the position and amount of solder applied to the printed circuit board are correct. The component mounter 13 has a component mounting head, and mounts required components on the printed circuit board. The reflow furnace 14 heats the printed circuit board on which the components are mounted, melting the solder and fixing the components to the board.

[0012] The visual inspection machine 15 inspects whether electronic components are mounted on the printed circuit board in the correct position without any defects. Specifically, the visual inspection machine 15 inspects the electronic components mounted on the printed circuit board for misalignment, floating components, missing mounting, soldering defects, etc. These inspections can be performed by visually inspecting the mounting board, that is, by measuring the height of the mounting board. The visual inspection machine 15 detects mounting defects by collating height data obtained by height measurement with design data for the board. The visual inspection machine 15 of this embodiment performs the height measurement using a light-section method.

[0013] [Height measurement using the light-cutting method] 2(A) to (C), the height measurement by the light-section method employed by the appearance inspection machine 15 will be explained. As shown in Fig. 2(A), the measurement target is a component C (workpiece) mounted on a board surface PS of a mounting board P. The hardware configuration will be described in detail later, but the appearance inspection machine 15 is equipped with a camera unit 4 (imaging section) and a line light source 5 (line light projection section).

[0014] The camera unit 4 has an imaging optical axis AX in a direction perpendicular to the board surface PS, and captures an image of the component C. The line light source 5 has a projection optical axis having a predetermined intersection angle θ with the imaging optical axis AX, and emits a line light SL along the projection optical axis. The line light SL is irradiated onto the component C to be measured. In this embodiment, the unit mounting the camera unit 4 and the line light source 5 has a mechanism for rotating around the imaging optical axis AX. This mechanism enables the line light source 5 to irradiate the component C to be measured with the line light SL from multiple directions.

[0015] 2(B) shows an image IM captured by the camera unit 4 at a certain scan position SC1 where the component C is irradiated with the line light SL. When the line light SL is irradiated onto an area including the component C, the camera unit 4 captures reflected light RL1 from the board surface PS around the component C and reflected light RL2 from the top surface of the component C. Because the line light SL is oblique light and the component C has height, the reflected light RL1 and RL2 are observed at different X coordinate positions on the image IM. Specifically, the reflected light RL1 appears at coordinate x11, and the reflected light RL2 appears at coordinate x12, which is downstream in the scanning direction from coordinate x11.

[0016] The point P0 in FIG. 2(A) where the line light SL is irradiated is treated as a point with a calculated height of 0. Then, as shown in FIG. 2(C), the principle of triangulation using the intersection angle θ allows height data to be obtained, such as the height of the coordinate x11 being h1 and the height of the coordinate x12 being h2. Thereafter, the camera unit 4 captures images at the scan positions SC2 and SC3 in sequence while moving the camera unit 4 and the line light source 5 downstream in the scan direction from the scan position SC1. As a result, the height data of the coordinates x21 and x22 is obtained at the scan position SC2, and the height data of the coordinates x31 and x32 is obtained at the scan position SC3. Needless to say, the actual scan pitch is much narrower than that shown in the example.

[0017] By integrating multiple height data acquired by scanning, it is possible to obtain three-dimensional shape data of component C. Note that the height data acquired at one scan position SC1, SC2, or SC3 is based on the result of reflected light RL1 and RL2 being irradiated at different X coordinate positions. For this reason, when integrating the data, a height table is created that matches, for example, the height data at coordinate x12 acquired in the area of ​​component C at scan position SC1 with the height data at coordinate x12 acquired in the area of ​​the board surface PS at the subsequent scan position.

[0018] 3(A) and (B) are diagrams explaining the drawbacks of component height measurement using the light-section method. The projection optical axis of the line light SL from the line light source 5 is inclined with respect to the vertical axis. Therefore, as shown in FIG. 3(A), when the line light SL is irradiated onto a component C having height, a shadow SH is generated where the line light SL does not hit the shadow of the component C. In the area of ​​the shadow SH, reflected light with a certain brightness does not enter the camera unit 4, so height measurement cannot be performed. FIG. 3(B) is a diagram showing the result of measuring the height data of the mounting board P shown in FIG. 3(A). The heights of the component C and the board surface PS can be measured, but the area of ​​the shadow SH is a missing part of the height data.

[0019] Fig. 3(C) is a diagram showing a solution to prevent the occurrence of the height data missing portion. A first line light source 5A and a second line light source 5B are used as the line light source 5, which are arranged opposite to each other in the scanning direction F. The first line light source 5A irradiates the first line light SL1 toward the substrate surface PS at a predetermined cross angle θ. The second line light source 5B is arranged in the opposite direction to the first line light source 5A across the imaging optical axis AX. The second line light source 5B irradiates the second line light SL2 toward the substrate surface PS from a direction 180 degrees different from the first line light SL at the same cross angle θ as the first line light SL1.

[0020] By using the second line light SL2, it is possible to illuminate the shadow area SH. By combining the height measurement result using the first line light SL1 and the height measurement result using the second line light SL2, it is possible to eliminate missing parts of the height data. However, even when a pair of line light sources 5A and 5B are used, missing parts of the height data may occur. In this embodiment, height measurement is possible for missing parts of the height data that cannot be eliminated even when a pair of line light sources 5A and 5B is used.

[0021] [Description of device configuration] Fig. 4 is a perspective view showing a schematic hardware configuration of the appearance inspection machine 15, and Fig. 5 is a block diagram showing an electrical configuration of the appearance inspection machine 15. The appearance inspection machine 15 includes a measurement device main body 2, a control device 3 (measurement unit), and a server device 30. The measurement device main body 2 executes an operation for measuring the height of the mounting board P. The measurement device main body 2 includes a base 21, a moving frame 22, a Y-axis moving mechanism 23 (scan driving unit / second moving mechanism), an X-axis moving mechanism 24 (scan driving unit / first moving mechanism), a slider 25, and a head 25H. The head 25H is equipped with the above-mentioned camera unit 4 and line light source 5.

[0022] The base 21 is a flat frame stand that supports the Y-axis moving mechanism 23 and also serves as a measurement stage 21S for the mounting board P. The mounting board P to be visually inspected is carried in from the reflow furnace 14 to the measurement stage 21S by a conveyor (not shown), and the mounting board P is carried out after inspection. The moving frame 22 is a gate-shaped frame extending in the X direction, and moves in the Y direction above the base 21. The moving frame 22 holds a head 25H via a slider 25.

[0023] The Y-axis moving mechanism 23 and the X-axis moving mechanism 24 function as a scan driving unit that moves the camera unit 4 and the line light source 5 to scan the part C (work). The Y-axis moving mechanism 23 is a mechanism that is arranged in a pair at both ends of the base 21 in the X direction and horizontally moves the moving frame 22 that holds the head 25H (camera unit 4 and line light source 5) in the Y direction (a second moving direction perpendicular to the first moving direction on the horizontal plane). The Y-axis moving mechanism 23 includes a Y-axis motor 231 made of a servo motor or the like, and a Y-axis ball screw shaft (not shown) connected to the Y-axis motor 231. The Y-axis ball screw shaft is screwed into a ball nut assembled to the moving frame 22. The X-axis moving mechanism 24 is a mechanism that is arranged on the moving frame 22 and horizontally moves the head 25H in the X direction (first moving direction). The X-axis moving mechanism 24 includes an X-axis motor 241 and an X-axis ball screw shaft (not shown) connected to the X-axis motor 241.

[0024] The slider 25 is a plate material that holds the head 25H, and is attached to the moving frame 22 so as to be movable in the X direction (scanning direction). The X-axis ball screw shaft is screwed into a ball nut attached to the slider 25. The slider 25 moves in the X direction along the moving frame 22 as the X-axis motor 241 rotates and drives the X-axis ball screw shaft. On the other hand, the moving frame 22 moves in the Y direction as the Y-axis motor 231 rotates and drives the Y-axis ball screw shaft. Therefore, the head 25H held by the slider 25 can be moved in the X and Y directions by the Y-axis moving mechanism 23 and the X-axis moving mechanism 24.

[0025] The head 25H includes a camera unit 4 and a pair of line light sources 5 (first line light source 5A and second line light source 5B) for measuring the height of the component C, a support plate 251, a light source holder 51, and a rotation mechanism 6. The support plate 251 is a plate extending in the Y direction from the slider 25, and supports the camera unit 4 and the line light source 5 rotatably around the imaging optical axis AX. The light source holder 51 is a wing-shaped support frame integrated with the camera unit 4, and supports the first line light source 5A with one wing piece and the second line light source 5B with the other wing piece. The rotation mechanism 6 is mounted on the support plate 251, and is a mechanism for rotating the camera unit 4 and the line light source 5 together around the imaging optical axis AX. The rotation mechanism 6 may be a mechanism for rotating the camera unit 4 and the light source holder 51 that holds the line light source 5 individually and independently.

[0026] The control device 3 controls various operations of the measurement device main body 2. Specifically, the control device 3 controls the Y-axis movement mechanism 23 and the X-axis movement mechanism 24 to cause the head 25H to scan the mounting board P, and obtains height data of the components C mounted on the mounting board P by a light section method based on an image acquired by the scan. The server device 30 relays data transmission between the control device 3 and the measurement device main body 2.

[0027] With reference to FIG. 5, the electrical configuration of the appearance inspection machine 15 will be described. Note that the server device 30 is omitted from FIG. 5. The measurement device main body 2 includes a Z-axis motor 261 and an R-axis motor 61 as elements not shown in FIG. 4. The Z-axis motor 261 is a drive source for moving the head 25H up and down in the Z-axis direction. The Z-axis motor 261 moves the head 25H up and down as necessary when the mounting board P to be measured has a large warp. Note that the Z-axis motor 261 may be omitted when the mounting board P is not expected to have a large warp. The R-axis motor 61 is a motor that serves as a drive source for the rotation mechanism 6, and generates a drive force for rotating the head 25H around the imaging optical axis AX.

[0028] The camera unit 4 includes a camera body 41 equipped with an imaging element such as a CMOS sensor, an imaging lens 42 that makes an optical image of the mounting board P incident on the camera unit 4, and a body 43 that incorporates an optical system that forms the optical image on the imaging surface of the imaging element. A light source holder 51 is attached to the body 43. A rotation mechanism 6 is also attached to the body 43. When the rotation mechanism 6 rotates the body 43, the entire camera unit 4 rotates around the imaging optical axis AX, and the pair of line light sources 5A, 5B attached to the light source holder 51 also rotate.

[0029] 6(A) to 6(C) are perspective views showing the rotation state of the head 25H. FIG. 6(A) shows a state where the rotation angle of the head 25H is 0 degrees. In this state, the pair of line light sources 5A and 5B are aligned along the X direction. The line light SL emitted by each of the line light sources 5A and 5B becomes a line light extending in the Y direction. FIG. 6(B) shows a state where the rotation angle of the head 25H is 45 degrees. In this case, the line light sources 5A and 5B are aligned on a line inclined at 45 degrees with respect to both the X direction and the Y direction, and the line light SL also becomes a line light extending in a direction inclined at 45 degrees with respect to both the X direction and the Y direction. FIG. 6(C) shows a state where the rotation angle of the head 25H is 90 degrees. In this state, the pair of line light sources 5A and 5B are aligned along the Y direction, and the line light SL becomes a line light extending in the X direction. In this way, the rotation mechanism 6 rotates the head 25H, so that the irradiation direction of the line light SL can be set to a required orientation.

[0030] The Y-axis motor 231, the X-axis motor 241, the Z-axis motor 261, and the R-axis motor 61 are respectively provided with a Y-axis encoder 232 (second encoder), an X-axis encoder 242 (first encoder), a Z-axis encoder 262, and an R-axis encoder 62. The Y-axis encoder 232 outputs a position detection signal that detects the Y-direction position of the moving frame 22 (head 25H) with a predetermined resolution. The X-axis encoder 242 outputs a position detection signal that detects the X-direction position of the head 25H with a predetermined resolution. The Z-axis encoder 262 outputs a position detection signal that indicates the Z-direction position of the head 25H. The R-axis encoder 62 outputs a position detection signal that indicates the rotational position of the head 25H.

[0031] The control device 3 is composed of a microcomputer or the like, and operates by executing a predetermined program so as to be functionally equipped with an imaging control unit 31, a scan control unit 32, a measurement processing unit 33, and an implementation data storage unit 34. Position detection signals are input to the control device 3 from the X-axis, Y-axis, Z-axis, and R-axis encoders 232, 242, 262, 62 via the server device 30.

[0032] The imaging control unit 31 controls the operation of the camera unit 4 and the line light source 5. Specifically, the imaging control unit 31 causes the line light source 5 to emit the line light SL, issues an imaging command to the camera unit 4 to perform an imaging operation at a predetermined timing, and receives image data obtained by the imaging as measurement data. The imaging control unit 31 causes the camera unit 4 to image the component C in synchronization with the position detection signal output by the Y-axis encoder 232 and the X-axis encoder 242 as the head 25H moves, thereby scanning the component C. For example, the imaging control unit 31 issues the imaging command each time the position detection signal reaches a predetermined count number. This makes it possible to set an arbitrary proportional relationship between the scan distance and the size in the scan direction on the imaging data. As a result, it becomes possible to obtain height data of the component C at the same pitch regardless of the direction of the scan.

[0033] The scan control unit 32 controls the Y-axis motor 231 and the X-axis motor 241 to move the head 25H, on which the camera unit 4 and the line light source 5 are mounted, in a required scan direction via the Y-axis moving mechanism 23 and the X-axis moving mechanism 24. The scan control unit 32 also operates the Z-axis motor 261 as necessary to adjust the height of the head 25H. Furthermore, the scan control unit 32 controls the R-axis motor 61 to rotate the head 25H and sets the irradiation direction of the line light SL from the line light source 5 to a required orientation.

[0034] The measurement processing unit 33 performs a calculation process to obtain height data of the component C by a light-section method based on the image acquired by the camera unit 4 during the scan. For example, the measurement processing unit 33 detects reflected light RL1 and RL2 as illustrated in FIG. 2B using an image processing method such as edge detection processing. The measurement processing unit 33 also performs a process to detect the presence or absence of missing parts in the height data. The missing parts correspond to the parts where the height data could not be measured due to the influence of the shadow part SH shown in FIG. 3A, for example. It is assumed that a scan (first scan) is performed in a certain scan direction / irradiation direction of the line light SL, and the missing parts are detected in the height data obtained based on the image acquired by the scan. In this case, the measurement processing unit 33 causes the imaging control unit 31 and the scan control unit 32 to perform a rescan (second scan) with the scan direction / irradiation direction of the line light SL set to a different orientation.

[0035] The mounting data storage unit 34 stores mounting data related to the mounting board P. The mounting data includes, for example, the type, XY size, height, number, and arrangement position on the board of the components C. In some embodiments described later, the mounting data stored in the mounting data storage unit 34 is utilized.

[0036] FIG. 7 is a perspective view showing a head 25HA according to a modified example. FIG. 4 shows an example in which the head 25H is rotated around the imaging optical axis AX by the rotation mechanism 6 to change the irradiation direction of the line light SL. FIG. 7 shows an example of a head 25HA in which the rotation mechanism 6 can be omitted. The head 25HA is configured such that a plurality of line light sources 5 are arranged at a predetermined pitch on a circumference centered on the imaging optical axis AX of one camera unit 4. Here, an example is shown in which ten line light sources 5a1, 5a2, 5b1, 5b2, 5c1, 5c2, 5d1, 5d2, 5e1, and 5e2 are arranged at an equal pitch on the circumference. By selecting a pair of line light sources 5a1 to 5e2 that are arranged opposite each other across the imaging optical axis AX, for example, the line light sources 5a1 and 5a2 or the line light sources 5b1 and 5b2, the irradiation direction of the line light SL can be changed.

[0037] [First embodiment of height measurement] 8A to 8D are schematic diagrams for explaining component height measurement according to the first embodiment. In the first embodiment, an example is shown in which a first scan is performed with the irradiation direction of the line light SL set to a default setting orientation, and then the head 25H is rotated to perform a second scan with the irradiation direction of the line light SL set to a different orientation. In FIG. 8 and the following figures, for the sake of simplicity, the head 25H is shown in a simplified form with the camera unit 4 shown as a substantially square and a pair of line light sources 5A and 5B shown as elongated rectangles arranged on either side of the camera unit 4. These also show the orientation of the imaging area of ​​the camera unit 4 and the irradiation directions of the line light SL1 and SL2 emitted by the line light sources 5A and 5B.

[0038] FIG. 8(A) shows the first scan. The target of height measurement is a mounting board P on which a relatively tall high component C1 and a relatively short low component C2 are mounted. The low component C2 is mounted in an area surrounded by the tall component C1. During the first scan, the scan control unit 32 operates the Y-axis motor 231 and / or the X-axis motor 241 with the rotation position of the head 25H set as a default setting position. This moves the head 25H in a predetermined scan direction F. In addition, the imaging control unit 31 causes the camera unit 4 to perform an imaging operation while emitting the first line light SL1 or the second line light SL2 from the first line light source 5A or the second line light source 5B. The same applies to the second scan that is executed later.

[0039] In the first scan, the scan direction F is the X direction (first scan direction), and the opposing direction of the pair of line light sources 5A and 5B is also the X direction. That is, the projection optical axis of the first line light SL1 or the second line light SL2 is a direction following the X direction, and the extension direction of the first line light SL1 or the second line light SL2 projected onto the measurement target is a Y direction perpendicular to the scan direction F. As is clear from FIG. 8(A), when the scan direction F is the X direction, an area where the low component C2 is sandwiched between two high components C1 arranged in the X direction is scanned. The measurement processing unit 33 executes a process of obtaining height data of the high component C1 and the low component C2 by the light section method based on the image acquired by the first scan.

[0040] Fig. 8(B) is a diagram showing the irradiation state of the first line light SL1 or the second line light SL2 when the first scan is performed in the scanning direction F and the line light projection direction of Fig. 8(A). The first line light SL1 emitted by the first line light source 5A is blocked by the high component C1 on the left side of the figure and cannot be irradiated to the low component C2. In addition, the second line light SL2 emitted by the second line light source 5B is also blocked by the high component C1 on the right side of the figure and cannot be irradiated to the low component C2.

[0041] When a high component C1 exists on only one side of the low component C2, as shown in FIG. 3B, either the first line light SL1 or the second line light SL2 can be irradiated onto the low component C2. However, when high components C1 exist on both sides of the low component C2, it may be impossible to irradiate both the first line light SL1 and the second line light SL2 onto the low component C2. In this case, the reflected light from the low component C2 does not enter the camera unit 4, and the measurement processing unit 33 cannot obtain height data for the mounting area of ​​the low component C2. In this case, the measurement processing unit 33 determines that there is a height data missing portion in the height measurement based on the first scan.

[0042] When a height data missing portion is detected, the measurement processing unit 33 executes a second scan with at least the irradiation direction of the line light SL1, SL2 in a different orientation. FIG. 8(C) is a diagram showing a first example of the second scan. In this first example, the scan direction F is maintained in the same X direction as the first scan, while the head 25H is rotated by about 45 degrees. The low component C2 is sandwiched between the high component C1 when viewed in the X direction and the Y direction, but is not sandwiched between the high component C1 when viewed in the intermediate orientation between the X direction and the Y direction.

[0043] By the rotation of the head 25H, the imaging area of ​​the camera unit 4 is also rotated about 45 degrees around the imaging optical axis AX. The irradiation direction (projection optical axis) of the line lights SL1 and SL2 also rotates around the imaging optical axis AX. That is, the relationship between the irradiation direction of the line lights SL1 and SL2 and the posture of the imaging area is maintained the same as in the first scan. The extension direction of the line lights SL1 and SL2 is inclined about 45 degrees with respect to the X direction. By performing the second scan with such an irradiation direction, either the first line light SL1 or the second line light SL2 can be irradiated onto the low component C2. Therefore, the measurement processing unit 33 can obtain the height data of the low component C2, which was a missing part of the height data, based on the image acquired in the second scan. In addition, the relationship between the posture of the imaging area and the irradiation direction of the line lights SL1 and SL2 is maintained the same in the first scan and the second scan, so that the height data can be derived efficiently.

[0044] FIG. 8(D) is a diagram showing a second example of the second scan. In this second example, the second scan is performed by setting the scan direction F to a direction different from that of the first scan. The scan direction F of the second scan is a direction (second scan direction) inclined by about 45 degrees with respect to the X direction, which is the scan direction F. The head 25H is rotated in the same manner as in the first example, and the imaging area of ​​the camera unit 4 and the irradiation direction of the line lights SL1 and SL2 are also rotated by about 45 degrees with respect to the setting of the first scan. In the second example, the relationship in which the scan direction F and the extending direction of the line lights SL1 and SL2 are perpendicular to each other is maintained in both the first scan and the second scan. Even in such a second example, the height data of the low component C2, which was a missing part of the height data, can be obtained by irradiating either the first line light SL1 or the second line light SL2 to the low component C2 in the second scan.

[0045] 9(A) to (D) are schematic diagrams for explaining other examples where missing parts of height data occur, and component height measurement examples in those cases. As shown in Fig. 9(A), on an actual mounting board P, components C may be mounted with a narrow component-to-component pitch W. If such a mounting board P is scanned such that the arrangement direction of the components C coincides with the scanning direction F, it may not be possible to obtain height data between the components C.

[0046] 9B, when two components C are arranged on the mounting board P with a narrow inter-component pitch W along the scanning direction F, there will be an area where neither the first line light SL1 nor the second line light SL2 reaches the board surface PS. When the line lights SL1 and SL2 are irradiated toward the board surface PS at a crossing angle θ (FIG. 2), if the height of the component C is H, then W=H / tanθ If the component pitch W is below this value, the line lights SL1 and SL2 are blocked by the component C. In this case, a missing portion of the height data occurs in the region of the component pitch W.

[0047] 9(C) and (D) show examples of height measurement of a mounting board P including the arrangement of components C as described above. Here, a mounting board P in which a plurality of components C are arranged in a matrix in the XY direction at a narrow pitch is shown as an example. In the first scan shown in FIG. 9(C), the scan direction F is set to the X direction (first scan direction). The opposing direction of the pair of line light sources 5A, 5B is also the X direction. Meanwhile, the extending direction of the first line light SL1 or the second line light SL2 projected onto the board surface PS is the Y direction. In this first scan, the area of ​​the pitch Wx of the components C arranged in the X direction may be a missing part of the height data, but the height data can be obtained for the area of ​​the pitch Wy of the components C arranged in the Y direction.

[0048] FIG. 9(D) shows the second scan. The scan direction F of the second scan is set to the Y direction rotated 90 degrees from the X direction. That is, the head 25H is rotated 90 degrees. As a result, the imaging area of ​​the camera unit 4 is rotated about 90 degrees around the imaging optical axis AX with respect to the first scan, and the irradiation direction of the line lights SL1 and SL2 is also rotated 90 degrees around the imaging optical axis AX. In this second scan, the area of ​​the pitch Wy of the parts C arranged in the Y direction may become a missing part of the height data. However, for the area of ​​the pitch Wx of the parts C arranged in the X direction that became a missing part of the height data in the first scan, the height data can be acquired. Therefore, the missing part of the height data can be eliminated by combining the measurement results of the first scan and the second scan.

[0049] [Second embodiment] In the second embodiment, an example is shown in which the scan direction F is limited to either the X direction or the Y direction in order to simplify the movement control of the head 25H. That is, an example is shown in which the control device 3 selects and operates either the Y-axis movement mechanism 23 or the X-axis movement mechanism 24 when executing the first scan and the second scan. When making the selection, the scannable width, the scan distance, and the like are referenced.

[0050] In height measurement of a mounting board P or the like as a measurement target, the head 25H must be moved so that the line light SL is irradiated to the entire area of ​​the measurement target. At this time, if the Y-axis moving mechanism 23 and the X-axis moving mechanism 24 are operated simultaneously, the scan direction F can be set to any direction. For example, as illustrated in FIG. 8(D), the middle direction between the X-axis direction and the Y-axis direction can be set as the scan direction F. However, in this case, the scan control unit 32 must synchronously control the Y-axis motor 231 and the X-axis motor 241, which complicates the drive control. To simplify the drive control, it is preferable to control the drive control so that only one of the Y-axis motor 231 or the X-axis motor 241 is operated during scanning. It is preferable to determine whether the X-axis direction or the Y-axis direction is selected as the scan direction F based on which direction takes the shortest time to scan the entire area of ​​the measurement target.

[0051] As explained based on Fig. 3(C), in order to avoid the influence of the shadow SH of the component C, it is necessary to scan so that both of the two line lights SL1 and SL2 pass over the measurement target. However, depending on the rotation angle of the head 25H, a difference in the scannable width occurs between the X direction and the Y direction. This point will be explained based on Figs. 10(A) to (D). Fig. 10 shows the imaging area 4A of the camera unit 4 and the line lights SL1 and SL2 projected into this imaging area 4A.

[0052] 10A shows the state where the rotation angle of head 25H is 0 degrees. At 0 degrees, line light SL1 and SL2 extend along the Y direction. Therefore, in an X-direction scan where the X direction is selected as the scan direction F, the scannable width X is the maximum width max. On the other hand, in a Y-direction scan where the Y direction is selected as the scan direction F, the scannable width Y is zero, making it impossible to measure.

[0053] Figure 10(B) shows the state where the rotation angle of the head 25H is 30 degrees. In the state of 30 degrees, in the X-direction scan, the region where both of the two line lights SL1 and SL2 can be irradiated becomes narrower than that in the state of 0 degrees. For this reason, the scanable width X becomes X = x1 which is smaller than the maximum width max. On the other hand, in the Y-direction scan, the region where both of the two line lights SL1 and SL2 can be irradiated becomes non-zero, and the scanable width Y becomes Y = y1. However, y1 < x1. Figure 10(C) shows the state where the rotation angle of the head 25H is 60 degrees. In the state of 60 degrees, since the extending directions of the line lights SL1 and SL2 approach the Y direction, the scanable width Y in the Y direction increases while the scanable width X in the X direction decreases. That is, the relationship is such that the scanable width X = x2, the scanable width Y = y2, and y2 > x2.

[0054] Figure 10(D) shows the state where the rotation angle of the head 25H is 90 degrees. In the state of 90 degrees, the line lights SL1 and SL2 extend along the X direction. For this reason, the scanable width Y of the Y-direction scan becomes the maximum width max, while the scanable width X of the X-direction scan becomes zero and measurement becomes impossible. As described above, it is necessary to select an appropriate one of the X direction or the Y direction as the scan direction F according to the rotation angle of the head 25H.

[0055] Figures 11(A) to (C) are diagrams for explaining a method for determining the scan direction F. The relationship between the rotation angle of the head 25H and the measurable width in the X-direction scan or the Y-direction scan can be obtained as follows. As shown in Figure 10(A), let the rotation angle of the head 25H be α, the measurable width when α = 0 degrees be L, and the distance between the two line lights SL1 and SL2 be D.

[0056] As shown in Figure 11(B), when the rotation angle of the head 25H is α and the X-direction scan is executed, the measurable width Lx is expressed by the following formula. Note that "abs" indicates the absolute value and "·" indicates multiplication respectively. Lx = abs(L·cosα) - abs(D·sinα) On the other hand, as shown in Fig. 11(C), when the rotation angle of the head 25H is α, the measurable width Ly in the case of performing Y-direction scanning is expressed by the following equation. Ly = abs(L·sinα) - abs(D·cosα)

[0057] The larger the values of the measurable widths Lx and Ly described above, the larger the measurement width in one scan. Therefore, by comparing the values of the X-direction measurable width Lx and the Y-direction measurable width Ly and selecting the larger one as the scan direction F, efficient height measurement can be performed. When the rotation angle is 45 degrees, the values of the measurable widths Lx and Ly are the same. In this case, the shorter the scan distance, the shorter the time required for scanning. Therefore, it is desirable to select the one with the shorter scan distance between the X-direction scan and the Y-direction scan.

[0058] Fig. 12 is a flowchart showing the scan direction determination process in the component height measurement according to the second embodiment. The scan control unit 32 of the control device 3 rotates the head 25H around the imaging optical axis AX to the required rotation angle α (step S1). This rotation angle α is, for example, a rotation angle at which the line light SL can be irradiated on the low component C2 surrounded by the high component C1 as illustrated in Fig. 8(C). Hereinafter, a process of selecting either the X-direction scan or the Y-direction scan is performed.

[0059] Next, the scan control unit 32 calculates the X-direction measurable width Lx and the Y-direction measurable width Ly using the above-described calculation formula based on the rotation angle α set in step S1 (step S2). Subsequently, the scan control unit 32 compares the values of the measurable widths Lx and Ly. First, it is determined whether the inequality Lx > Ly is satisfied (step S3). When Lx > Ly is satisfied (YES in step S3), the scan control unit 32 selects the X-direction scan with a wider measurement width (step S4). On the other hand, when Lx > Ly is not satisfied (NO in step S3), it is determined whether the inequality Lx < Ly is satisfied (step S5). When Lx < Ly is satisfied (YES in step S5), the scan control unit 32 selects the Y-direction scan (step S6).

[0060] On the other hand, when Lx < Ly is not satisfied (NO in step S5), it means Lx = Ly. In this case, the scan control unit 32 compares the scan distance when X-direction scanning is adopted with the scan distance when Y-direction scanning is adopted (step S7). For example, in the example of FIG. 8(B), in the first scan, the region sandwiched between the two high components C1 becomes the missing part of the height data. When re-measuring this missing part region in the second scan, it is determined which of X-direction scanning or Y-direction scanning results in a shorter scan distance. For example, if the missing part region is a rectangular region that is long in the X direction, Y-direction scanning requires a shorter scan distance for the missing part region, which can contribute to speeding up the height measurement. Therefore, when the X-direction scan distance is longer than the Y-direction scan distance (YES in step S7), the scan control unit 32 selects Y-direction scanning (step S8). Conversely, when the Y-direction scan distance is longer than the X-direction scan distance (NO in step S7), the scan control unit 32 selects X-direction scanning (step S9).

[0061] [Third Embodiment] In the third embodiment, an example of determining the scan direction F using the mounting data of the component C is shown. What components C are mounted on the mounting substrate P and in what layout are predetermined by the mounting data. The mounting data is information regarding the shape of the component C and the mounting position on the substrate, and is stored in the mounting data storage unit 34. By utilizing this mounting data, it is possible to detect the irradiation direction or even the scan direction F of the line light SL in which no height data missing part occurs or in which the height data missing part is minimized. In the third embodiment, an example is shown in which the measurement processing unit 33 reads the mounting data from the mounting data storage unit 34 and determines the presence or absence of the occurrence of the missing part of the height data.

[0062] 13(A) to (E) are schematic diagrams for explaining component height measurement according to the third embodiment. Assume that the attitude of head 25H including camera unit 4 and line light sources 5A and 5B and scan direction F are set in the default state as shown in FIG. 13(A). Before executing a scan, measurement processing unit 33 acquires mounting data for mounting board P to be measured from mounting data storage unit 34. The simplest example is a case where no missing parts of height data occur even if a scan is executed in the default state. In this case, height measurement is completed by simply executing the first scan in the default state. The second scan is unnecessary.

[0063] Figures 13(B) and (C) show examples of acquiring mounting data. Figure 13(B) corresponds to the example of arrangement of components C1 and C2 shown in Figure 8(A), and Figure 13(C) corresponds to the example of matrix arrangement of component C shown in Figure 9(C). By acquiring the mounting data, a three-dimensional model of the mounting board P after components are mounted can be created. The measurement processing unit 33 uses this three-dimensional model to determine the scanning mode. As described above, in both of the examples of Figures 13(B) and (C), when scanning is performed in the default state, missing parts of the height data will occur.

[0064] In this case, the measurement processing unit 33 performs a simulation in which the irradiation orientation of the line light SL and the scanning direction F are variously changed, and determines the optimal scanning mode. Figures 13(D) and (E) respectively show examples of determining the scanning mode when the mounting data of Figures 13(B) and (C) are acquired. Figure 13(D) corresponds to the scanning mode of Figure 8(C), and Figure 13(E) corresponds to the scanning mode of Figure 9(D).

[0065] For example, when the mounting data of FIG. 13(B) is acquired, it is determined that no missing portion of the height data occurs in the scan mode in which the head 25H has a rotation angle as shown in FIG. 13(D). In this case, only the first scan is executed in the scan mode of FIG. 13(D) to complete the height measurement of the mounting board P. In the scan mode of FIG. 13(D), if missing portions of the height data occur in other parts, for example, the first scan is executed in the default scan mode of FIG. 13(A) and the second scan is executed in the scan mode of FIG. 13(D) to complement the height data. Also, when the mounting data of FIG. 13(C) is acquired, missing portions of the height data occur between the component pitches in the Y direction in the scan mode of FIG. 13(E). Therefore, it is determined that the first scan is executed in the default scan mode of FIG. 13(A) and the second scan is executed in the scan mode of FIG. 13(E).

[0066] [Fourth embodiment] In the fourth embodiment, when a missing portion of height data is detected in the first scan, it is determined whether or not the cause of the missing portion is due to the scan direction, and if the missing portion is due to the scan direction, a second scan is performed. A missing portion of height data is not generated only due to a shadow portion SH of a component C. For example, when an opening or a cutout portion exists in a mounting board P, the reflected light from the board surface PS cannot be detected in those parts, and the height data is missing. Even if a second scan is performed on such a missing portion, no height data is obtained, resulting in a waste of man-hours. Therefore, even if a region of missing height data occurs, it is desirable to determine whether the missing portion has failed to measure the height due to the scan direction, and then perform a second scan on the missing portion region.

[0067] An example of the determination as to whether or not to perform a second scan on a height data missing portion is shown. Figures 14(A) and (B) are schematic diagrams showing one aspect of the determination. Here, when a height data missing portion is adjacent to a data-containing area from which height data has been acquired in the scanning direction F, the missing portion is determined to be a missing portion caused by the scanning direction.

[0068] FIG. 14(A) shows a case where the mounting board P1 to be measured has a component layout in which a low component C2 is arranged between two high components C1. As shown in FIG. 14(A)(A-1), a first scan for measuring the height of the mounting board P1 is performed with the direction in which the two high components C1 are lined up as the scanning direction. FIG. 14(A)(A-2) shows an image IM1 of height data obtained based on the first scan. The two high components C1 are shown as data-present areas in which height data higher than the height of the board surface PS (mounting surface) has been obtained. Meanwhile, two shadow areas SH1 and SH2, whose heights have not been detected, are shown in the image IM1. In one of the shadow areas SH1, an isolated area CA that is elongated in a direction perpendicular to the scanning direction appears.

[0069] One of the shadow areas SH1 is adjacent to the two high components C1, which are data-containing areas, in the scanning direction. In this case, it is highly likely that the measurement of the shadow area SH1 has failed because the line light SL was blocked by the high components C1. In fact, no height data has been obtained for the low component C2 sandwiched between the high components C1. The isolated area CA is an error area that is detected as a data-containing area due to diffuse reflection of the line light SL, etc. Normally, a component with this shape does not exist, so it is deleted as noise. On the other hand, the other shadow area SH2 is not adjacent to any of the high components C1 in the scanning direction.

[0070] (A-3) in FIG. 14(A) shows an example of determining the execution area of ​​the second scan when the situation of (A-2) is obtained. The shadow part SH1 adjacent in the scanning direction to the data-containing area corresponding to the two high-rise components C1 is determined as the rescan area RS1, which is the target area of ​​the second scan. On the other hand, the shadow part SH2 not adjacent in the scanning direction to the data-containing area is not treated as the rescan area RS1. In the second scan performed later, the height of the rescan area RS1 is measured by changing the irradiation direction of the line light SL, etc. According to this embodiment, the second scan is not performed unnecessarily, and the height measurement can be speeded up.

[0071] Fig. 14(B) shows a case where the mounting board P2 to be measured has a cutout portion PD2. As shown in Fig. 14(B) (B-1), the mounting board P2 has a cutout portion PD2, which is formed by cutting out a part of the mounting board P2, adjacent to the downstream side in the scanning direction of the mounted component C. Fig. 14(B) (B-2) shows an image IM2 of height data obtained based on the first scan. The mounting area of ​​the component C is shown as a data-present area having height data higher than the board surface PS. On the other hand, the area of ​​the cutout portion PD2 is a shadow area SH3 with no height data.

[0072] (B-3) in FIG. 14(B) shows an example of determining the execution area of ​​the second scan when the situation of (B-2) is obtained. In this case, although the shadow portion SH3 is adjacent to the data-containing area corresponding to part C, the entire area is not set as the target area of ​​the second scan. Of the shadow portion SH3, only the area that is directly adjacent to the data-containing area of ​​part C in the scanning direction, that is, the area located downstream in the scanning direction, is set as the rescan area RS2. This rescan area RS2 also corresponds to the cutout portion PD2, so as a result, height data is not measured in the second scan. However, since the execution area of ​​the second scan is limited, it can contribute to speeding up height measurement.

[0073] 15(A) and (B) are schematic diagrams showing other examples of judgment as to whether or not to execute a second scan for a height data missing portion. Here, an example is shown in which a height data missing portion adjacent to a data-containing region in the scan direction F is judged to be caused by the scan direction when the missing portion has less than a predetermined number of pixels in the image obtained by the first scan. In the example of FIG. 14, even the cutout portion PD2 is determined to be the target of the second scan as long as it is adjacent to a data-containing region in the scan direction. In this judgment example, an example is shown in which this defect is suppressed.

[0074] FIG. 15(A) shows a case where the mounting board P1 to be measured has a component layout in which a low component C2 is arranged between two high components C1, similar to FIG. 14(A). Assume that a first scan for measuring the height of the mounting board P1 is performed with the direction in which the two high components C1 are lined up as the scanning direction. As shown in (A-2) of FIG. 15(A), the area corresponding to the two high components C1 is an area with data, and between them, a shadow part SH1 where height is not detected and an isolated area CA appear. When determining whether or not to perform a second scan, the isolated area CA is ignored as noise, and the width d1 in the scanning direction of the shadow part SH1, which is a missing part of the height data, is evaluated by the number of pixels on the image. Here, since the width d1 of the shadow part SH1 is a missing part less than a predetermined number of pixels n, it is determined that the shadow part SH1 is to be treated as the object of the second scan.

[0075] FIG. 15(B) shows a case where the mounting board P2 to be measured has a cutout portion PD2, similar to FIG. 14(B). The mounting board P2 has the cutout portion PD2 adjacent to the component C on the downstream side in the scanning direction. As shown in (B-2) of FIG. 15(B), the area corresponding to the component C is a data-available area, and the area of ​​the cutout portion PD2 is a shadow portion SH3 with no height data. As in the above, the width d2 of the shadow portion SH3 in the scanning direction is evaluated by the number of pixels on the image. Here, since the width d2 of the shadow portion SH3 is a missing portion with a predetermined number of pixels n or more, it is determined that the shadow portion SH3 is not to be treated as a target for the second scan.

[0076] The predetermined number of pixels n can be set to any value equal to or greater than 0. For example, when a height data missing portion is detected, if the entire portion is to be rescanned, n=0 may be set. Alternatively, the number of pixels n may be dynamically set based on the relationship between the average height of the periphery of the height data missing portion and the irradiation angle of the line light SL. The number of pixels n may be set based on the number of pixels for which height data is complemented in image processing. For example, if there are three or fewer pixels without height data, n=4 is set in the case of setting to derive height data for the pixels without data in the complementation process. In this way, the criterion for determining that the height data missing portion is a trigger for executing the second scan can be set arbitrarily based on the number of pixels n.

[0077] 16 is a flowchart showing a scan area determination process in component height measurement according to the fourth embodiment. The scan control unit 32 of the control device 3 executes a first scan defined by default settings to measure the height of the mounting board P to be measured (step S11). Next, the measurement processing unit 33 obtains height data and height data missing parts based on the image obtained by the first scan (step S12).

[0078] Next, the measurement processing unit 33 judges whether or not there is an isolated area CA in the height data missing portion, in which the height data is unnaturally isolated, as shown in Fig. 14(A) (step S13). If an isolated area CA is detected (YES in step S13), the area is noise, so the measurement processing unit 33 performs a process to delete the isolated area CA (step S14). If an isolated area CA is not detected (NO in step S13), the measurement processing unit 33 judges whether or not there is a data-containing area adjacent to the height data missing portion, in which height data higher than the substrate surface PS is detected (step S15).

[0079] If the data-containing region exists (YES in step S15), the measurement processing unit 33 judges whether the height data missing portion is a missing portion corresponding to a shadow in the scanning direction (step S16). That is, the measurement processing unit 33 judges whether the height data missing portion detected in step S2 is a missing portion adjacent to the data-containing region in the scanning direction. If it is an adjacent missing portion in the scanning direction (YES in step S16), the measurement processing unit 33 judges whether the height data missing portion is a missing portion having a width of equal to or greater than a predetermined number of pixels n in the scanning direction on the image (step S17).

[0080] If it is determined that the missing portion has a width equal to or greater than the number of pixels n (YES in step S17), the measurement processing unit 33 determines that the height data missing portion is a missing portion that requires rescanning. In this case, it is determined whether or not all specified height measurements have been completed (step S18). If the height measurements are not completed (NO in step S18), the scan control unit 32 changes the rotation angle of the head 25H and the scan direction F as necessary (step S20), and returns to step S11 to execute a second scan as a rescan. For example, the rescan is executed by changing the rotation angle by 15 degrees at a time.

[0081] When all height measurements have been completed (YES in step S18), the measurement processing unit 33 stores the height measurement data for the mounting board P that was the measurement target in the memory area of ​​the control device 3 and updates the data (step S19). On the other hand, if there is no data-containing area in step S15 (NO in step S15), if the missing parts are not adjacent in the scanning direction in step S16 (NO in step S16), or if it is determined in step S17 that the missing part has a width equal to or greater than the number of pixels n (YES in step S17), the measurement processing unit 33 determines that rescanning is not necessary (step S21) and ends the process.

[0082] [Fifth embodiment] In the fifth embodiment, an example is shown in which a desirable scan mode is detected in advance using a model board. In summary, the scan control unit 32 executes multiple scans on the model board with the line lights SL1 and SL2 oriented in different directions, and selects a scan suitable for use as the first scan from the multiple scans. Then, in subsequent height measurements of the mounting board P that is the same as the model board, the height measurement is performed in the selected scan mode.

[0083] 17(A) to (C) are schematic diagrams for explaining component height measurement according to the fifth embodiment. In this embodiment, a model substrate PM as shown in FIG. 17(A) is prepared. The model substrate PM is a non-defective substrate on which components C are mounted in a predetermined arrangement on a substrate according to the substrate design of a certain mounted substrate product. Here, like the example product in FIG. 8(A), it has a layout in which one low component C2 is surrounded by four high components C1.

[0084] Before measuring the height of the mounted board product, the control device 3 executes a height measurement operation on the model board PM. In this height measurement, the scan control unit 32, for example, rotates the head 25H sequentially to perform a plurality of height measurements with the irradiation directions of the line lights SL1 and SL2 in different orientations. Fig. 17(A) shows an example in which the rotation angle of the head 25H is changed sequentially to 0 degrees, 45 degrees, and 90 degrees, and the model board PM is scanned in the scan directions F1, F2, and F3, respectively. In practice, it is desirable to scan the model board PM while changing the rotation angle of the head 25H at a small pitch of about 15 degrees.

[0085] Based on the images acquired by each scan, the measurement processing unit 33 obtains height data of the model substrate PM. At this time, the measurement processing unit 33 identifies missing parts of the height data in each scan and evaluates how accurately the height measurement was performed based on the mounting data. In FIG. 17(A), when the rotation angle of the head 25H is 0 degrees and 90 degrees, the height measurement of the low component C2 cannot be performed, and therefore the scan mode cannot be evaluated as being optimal. On the other hand, when the rotation angle is 45 degrees, the height measurement including the low component C2 is possible. Therefore, the measurement processing unit 33 adopts the rotation angle of the head 25H of 45 degrees as the scan mode when the mounting substrate P on which the components C1 and C2 are mounted in the same arrangement as the model substrate PM is the target of height measurement.

[0086] 17(B) and (C) show the scanning modes for the mounting board P, which is the same as the model board PM, which are performed subsequently. These are the same as the scanning modes shown in FIG. 8(C) and (D) of the first embodiment. FIG. 17(B) shows an example in which scanning is performed with the rotation angle of the head 25H set to 45 degrees while maintaining the scanning direction F1 with a rotation angle of 0 degrees. FIG. 17(C) shows an example in which the rotation angle of the head 25H is set to 45 degrees and the scanning direction F2 is set according to this rotation angle.

[0087] According to the fifth embodiment, a plurality of scans are performed in advance using the model substrate PM, and it is possible to find the optimum scan in which height data loss is least likely to occur. Then, for a mounting substrate P that is the same as the model substrate PM, the aspect of the optimum scan is applied to at least the first scan, making it possible to perform height measurement without waste.

[0088] In the fifth embodiment, when mounting data exists for a component C from which its height, volume, and area can be calculated, a scan mode can be selected in which the height, volume, and area obtained from the measurement values ​​in each scan are closest to the mounting data. Fig. 18 shows an example in which the scan direction is evaluated for a low component C2 and a high component C1 based on the volume ratio, which is the ratio between the volume calculated from the mounting data and the volume calculated by actual measurement in each scan. The closer the volume ratio is to 100%, the more accurate the measurement is.

[0089] 18(A) shows the volume ratio of the low component C2 and the high component C1 when the scan direction and the rotation angle of the head 25H are 0 degrees. As mentioned above, when the angle is 0 degrees, the low component C2 is in the shadow of the high component C1, and accurate height measurement cannot be performed. For this reason, the volume ratio of the low component C2 is a low value of 1%. On the other hand, there is no problem with the measurement of the high component C1, so the volume ratio is a high value of 95%.

[0090] FIG. 18(B) shows the volume ratio when the scan direction and rotation angle of head 25H are 45 degrees. When the angle is 45 degrees, the line lights SL1 and SL2 can be irradiated to the low component C2 as well. As a result, a high volume ratio of 99% is obtained for the low component C2. A high volume ratio of 97% is also obtained for the high component C1. FIG. 18(C) shows the volume ratio when the rotation angle is 90 degrees. Even in this case, the low component C2 is in the shadow of the high component C1, making it impossible to perform accurate height measurement. Therefore, the volume ratio of the high component C1 is 94%, but the volume ratio of the low component C2 is a low value of 2%.

[0091] According to the above results, accurate height measurement cannot be performed at least in the mounting areas of low components C2 and high components C1 when the rotation angle is 0 degrees or 90 degrees. Therefore, scanning with a rotation angle of 45 degrees is selected. In an actual mounting board P, there are multiple mounting areas, and each mounting area has a desired scanning direction. It is preferable to set the optimal scanning mode for the entire mounting board P by, for example, sorting the mounting areas or components that have the same desired scanning direction.

[0092] 19 is a flowchart showing a scan direction determination process in component height measurement according to the fifth embodiment when mounting data is available. The scan control unit 32 of the control device 3 executes a scan defined by default settings on the model board PM to measure the height of the mounted components C (step S31). Next, the measurement processing unit 33 obtains height data for each component C on the model board PM. Furthermore, the measurement processing unit 33 reads out the mounting data from the mounting data storage unit 34, and calculates a volume ratio from the volume based on the actual measured height data of the components C and the volume of the component C1 derived from the actual measurement data (step S32).

[0093] Next, it is confirmed whether or not height measurement of the model board PM has been completed at a pre-specified rotation angle and scan direction of the head 25H (step S33). If all height measurements are incomplete (NO in step S33), the scan control unit 32 changes the rotation angle or scan direction of the head 25H (step S35) and executes a new scan (step S31). On the other hand, if all height measurements are completed (YES in step S33), the measurement processing unit 33 identifies, for each component C, the scan direction that has provided the closest result to the mounting data among all the scans attempted, and stores this (step S34).

[0094] The above is an example of a method for determining the scan direction when mounting data can be used. When mounting data cannot be used, the optimal scan direction can be selected based on the relationship between the area of ​​the missing parts of the height data and the scan direction. Figures 20(A) to (C) are diagrams showing the relationship between the shadow areas SH1, SH21, SH22, and SH3, which are missing parts of height data, and the scan direction when measuring the height of component C. Figures 20(A), (B), and (C) respectively show the measurement results when the scan direction and the rotation angle of head 25H are 0 degrees, 45 degrees, and 90 degrees.

[0095] Based on the images acquired by each scan in Fig. 20(A) to (C), a data-containing region, which is the region of part C, is identified. Next, the area of ​​the missing part of height data adjacent to this data-containing region in the scanning direction is calculated. As shown in Fig. 20(A), when the rotation angle is 0 degrees, the long side of the rectangular part C is perpendicular to the scanning direction, so a relatively large shadow part SH1, i.e., the missing part, is exposed. In contrast, when the rotation angle is 45 degrees in Fig. 20(B), shadow parts SH21 and SH22 with relatively small areas are exposed at the corners of the part C1 on the downstream side in the scanning direction. When the rotation angle is 90 degrees in Fig. 20(C), a shadow part SH3 with an area larger than the sum of SH21 and SH22 is exposed on the short side of the part C.

[0096] Among these scans in Figures 20(A) to (C), the scan that produces the smallest area of ​​the missing portion is selected as the first scan. In this example, the shadow portions SH21 and SH22 detected in the scan in Figure 20(B) set at a rotation angle of 45 degrees have the smallest area compared to the others. In other words, a rotation angle of 45 degrees is the scan that is least likely to produce missing portions in the height data. Therefore, at least a scan with a rotation angle of 45 degrees of head 25H is selected as the first scan.

[0097] Fig. 21 is a flowchart showing a scan direction determination process when mounting data cannot be used in component height measurement according to the fifth embodiment. The scan control unit 32 of the control device 3 executes a scan defined by default settings on the model board PM, and causes height measurement of the mounted components C to be performed (step S41). Next, the measurement processing unit 33 executes a process to determine height data missing parts for the model board PM (step S42). The process of this step S42 is similar to the processes of steps S12 to S17 in Fig. 16 described above, and a description thereof will be omitted here.

[0098] Thereafter, the measurement processing unit 33 performs a process of calculating the area of ​​the height data missing portion generated in the scan (step S43). Then, it is confirmed whether the height measurement of the model substrate PM is completed at the rotation angle and scan direction of the head 25H designated in advance (step S44). If all the height measurements are incomplete (NO in step S44), the scan control unit 32 changes the rotation angle or scan direction of the head 25H (step S46) and executes a new scan (step S41). On the other hand, if all the height measurements are completed (YES in step S44), the measurement processing unit 33 selects the scan that minimizes the area of ​​the height data missing portion (step S45). The scan mode selected here is used for the height measurement of the same mounting substrate P as the model substrate PM to be performed later.

[0099] [Sixth embodiment] In the sixth embodiment, an example of obtaining high-resolution height data of a specific part is shown. For example, it may be required to obtain the shape of a highly important part with high resolution. In this case, a first scan is performed on the part, and at least a second scan is performed assuming that there is a missing portion of the height data in the first scan. In other words, regardless of the presence or absence of a missing portion of the height data, multiple scans are performed on the part. Then, height data obtained from images obtained in at least the first and second scans is synthesized to obtain the height data of the part.

[0100] 22(A) to (D) are schematic diagrams for explaining component height measurement according to the sixth embodiment. The measurement target is a specific component CP mounted on a mounting board P. The specific component CP is an important component such as a large scale integrated circuit component. As shown in FIG. 22(A), the specific component CP is scanned multiple times by changing the rotation angle of the head 25H, i.e., the irradiation directions of the line lights SL1 and SL2. FIG. 22(A) shows an example in which a first scan with the X direction as the scan direction F1 and a second scan with the Y direction as the scan direction F2 are performed on the specific component CP.

[0101] FIG. 22(B) shows the height data of the specific part CP obtained based on the image acquired in the first scan, and the shadow part SHx, which is a height data missing part. The shadow part SHx appears on the X side XS of the specific part CP, but there is no shadow part on the Y side YS. FIG. 22(C) shows the height data of the specific part CP based on the second scan, and the shadow part SHy. The shadow part SHy appears on the Y side YS of the specific part CP, but there is no shadow part on the X side XS. In the height measurement by the first scan, the height data of the X side XS is not determined. In addition, in the height measurement by the second scan, the height data of the Y side YS is not determined. However, as shown in FIG. 22(D), by combining the height data obtained by the first scan and the second scan, the uncertain parts due to the shadow parts SHx and SHy can be eliminated. Therefore, the height data of the specific part CP can be obtained with high precision.

[0102] 23 is a flowchart showing a high-resolution component height data creation process according to the sixth embodiment. The scan control unit 32 of the control device 3 executes a scan defined by default settings for the specific part CP, and measures the height of the specific part CP (step S51). Based on this height measurement, the measurement processing unit 33 obtains the height data and the shadow parts SHx and SHy of the specific part CP (step S52).

[0103] 22(B)-(D), it is confirmed whether or not the height measurements required for data synthesis have been completed (step S53). If all height measurements are incomplete (NO in step S53), the scan control unit 32 changes the rotation angle or scan direction of the head 25H (step S54) and executes a new scan (step S51). On the other hand, if all height measurements are completed (YES in step S53), the measurement processing unit 33 executes a synthesis process of the height data (step S55).

[0104] In step S55, as shown in Figures 22C and 22D, if the shadows SHx and SHy are present on only one of the X-side edge XS and the Y-side edge YS of the specific part CP, a synthesis process is performed in which the height data of the other side is used as is. That is, the height data of the Y-side edge YS obtained in the first scan and the height data of the X-side edge XS obtained in the second scan are used as is to create the height data of the specific part CP. In contrast, in multiple scans, the shadows SHx and SHy may appear on both the X-side edge XS and the Y-side edge YS. In this case, the height data can be created by using the average, median, maximum value, or minimum value of the height data obtained in multiple scans.

[0105] [Other modified embodiments] Although various embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and for example, the following modified embodiments can be adopted.

[0106] (1) In the above embodiment, an example was shown in which the camera unit 4 and the line light sources 5A and 5B were rotated together by rotating the head 25H around the imaging optical axis AX. Alternatively, the irradiation direction of the line light SL may be changed by rotating only the line light sources 5A and 5B. In the above example, as shown in FIG. 24(A), the camera unit 4 and the line light sources 5A and 5B are rotated together so that the relationship between the posture of the imaging area 4A of the camera unit 4 and the irradiation direction of the line light SL1 and SL2 is maintained. In contrast, the modified example shown in FIG. 24(B) shows an example in which the camera unit 4 is not rotated and only the line light sources 5A and 5B are rotated. In this case, the relationship between the posture of the imaging area 4A and the irradiation direction of the line light SL1 and SL2 changes from the case of FIG. 24(A). The scanning direction can be set to a direction perpendicular to the extension direction of the line light SL1 and SL2.

[0107] (2) In general, the image data captured by the camera unit 4 is transferred to the control device 3 for all pixels. Alternatively, in order to speed up processing, only a portion of the image data may be transferred. FIG. 25 is a schematic diagram showing an example of limiting the image data to be used. In the light section method, the image data required is the peripheral area of ​​the line lights SL1 and SL2. For example, assume that the line lights SL1 and SL2 are irradiated as shown in FIG. 24(B). In this case, instead of transferring the image data of the entire imaging area 4A provided by the CMOS sensor or the like of the camera body 41, only the image data present in the imaging area ROI of the line lights SL1 and SL2 is cut out and transferred as shown in FIG. 25. This allows for faster data processing.

[0108] [Inventions included in the above embodiments] A workpiece height measuring device according to one aspect of the present invention comprises an imaging unit having an imaging optical axis in a vertical direction and capturing an image of the workpiece; a line light projection unit having a projection optical axis having a predetermined intersection angle with the imaging optical axis and capable of irradiating the workpiece with line light from a plurality of orientations; a scan drive unit moving the imaging unit and the line light projection unit to scan the workpiece; and a measurement unit controlling the scan drive unit to perform the scan and determining height data of the workpiece by a light section method based on the image acquired by the scan, wherein the measurement unit performs a first scan by irradiating the line light onto the workpiece from a predetermined irradiation direction, and determines whether or not there are any missing portions in the height data of the workpiece in the height data obtained based on the image acquired in the first scan, and if any missing portions are detected, performs a second scan in which the irradiation direction of the line light is in a different orientation from that of the first scan.

[0109] According to this workpiece height measuring device, if a missing portion is detected in the height data obtained by the first scan, a second scan is performed in which the irradiation direction of the line light is set to a different direction from that of the first scan. If there are multiple workpieces of different sizes or the workpieces are densely packed, the first scan may result in workpieces not being irradiated with the line light due to being in the shadow of another workpiece. Alternatively, if the workpiece has surface irregularities, the first scan may result in shadow areas where the line light is not irradiated due to being blocked by convex parts. However, by performing the second scan, it becomes possible to perform height measurement again for these shadow areas. Therefore, the height of the workpiece can be accurately measured.

[0110] In the above-mentioned work height measuring device, the measurement unit can execute the first scan by setting the scan direction to a predetermined first scan direction while setting the posture of the imaging area of ​​the imaging unit and the irradiation direction of the line light to predetermined conditions, and can execute the second scan by rotating the imaging area around the imaging optical axis while maintaining the scan direction in the first scan direction, and changing the orientation of the irradiation direction of the line light so that the relationship between the irradiation direction of the line light and the posture of the imaging area is maintained the same as in the first scan.

[0111] According to this workpiece height measuring device, the first scan and the second scan are performed without changing the scan direction. Even without changing the scan direction, the orientation of the image capturing area and the irradiation direction of the line light are different between the first scan and the second scan. Therefore, the height of the workpiece can be measured in the second scan for an area where there is a missing portion in the height data. Furthermore, the relationship between the posture of the image capturing area and the irradiation direction of the line light is maintained the same between the first scan and the second scan, so that the height data can be derived efficiently.

[0112] In the above-mentioned work height measuring device, the measurement unit may execute the first scan by setting the scan direction to a predetermined first scan direction while setting the posture of the imaging area of ​​the imaging unit and the irradiation direction of the line light to predetermined conditions, set the scan direction to a second scan direction different from the first scan direction, rotate the imaging area around the imaging optical axis according to the second scan direction, and change the orientation of the irradiation direction of the line light so that the relationship between the irradiation direction of the line light and the posture of the imaging area is maintained the same as in the first scan, thereby executing the second scan.

[0113] According to this workpiece height measuring device, by simply changing the scanning direction, height measurement can be performed in a second scan for an area where there is a missing portion in the workpiece height data.

[0114] In the above-mentioned work height measuring device, it is desirable that the scan driving unit includes a first movement mechanism that moves the imaging unit and the line light projection unit horizontally in a first movement direction, and a second movement mechanism that moves them horizontally in a second movement direction perpendicular to the first movement direction in a horizontal plane, and that the measurement unit selects and operates either the first movement mechanism or the second movement mechanism when performing the first scan and the second scan.

[0115] According to this workpiece height measuring device, when performing a scan operation, the scan driving unit drives only one of the first moving mechanism or the second moving mechanism, which simplifies the drive control of the scan driving unit.

[0116] In this case, it is preferable that the measurement unit selects the first moving mechanism or the second moving mechanism, whichever has a shorter scan distance. According to this aspect, the total scan distance required to scan the workpiece can be shortened, which contributes to speeding up height measurement.

[0117] In the above-mentioned work height measuring device, it is preferable that the work is a board on which a plurality of components are mounted, and the measurement unit acquires component mounting data including information regarding the shape of the components and their mounting positions on the board, and determines whether or not there are any missing portions in the height data based on the component mounting data.

[0118] According to this workpiece height measuring device, it is possible to grasp in advance the relationship between the irradiation direction or scanning direction of the line light and the location of the missing parts in the height data based on the component mounting data, and therefore it is possible to set in advance the irradiation direction or scanning direction of the line light that has fewer missing parts.

[0119] In the above-mentioned work height measuring device, when a missing portion of the height data is detected, it is desirable that the measurement unit determines whether or not the cause of the missing portion is due to the scanning direction, and if the missing portion is due to the scanning direction, executes the second scan.

[0120] A missing portion of height data may occur, for example, when an opening or a notch exists in the installation base of the workpiece. According to the above-mentioned workpiece height measuring device, the second scan is performed only when the missing portion of height data is caused by the scan direction. Therefore, the second scan is not performed unnecessarily.

[0121] In the above-mentioned work height measuring device, the work is mounted on a substrate mounting surface, and the measurement unit identifies a data-containing area in which height data higher than the height of the mounting surface is obtained, and can perform the second scan when the missing portion is adjacent to the data-containing area in the scanning direction.

[0122] When a height data missing portion is adjacent to a data-containing area in the scanning direction, the missing portion is likely to be caused by a shadow cast by the line light. In such a case, the above-mentioned workpiece height measuring device determines that the data missing portion is caused by the scanning direction. Therefore, it is possible to accurately determine whether or not a second scan is required.

[0123] In the above-mentioned work height measuring device, the measuring unit can perform the second scan when the missing portion adjacent to the data-containing area in the scanning direction is a missing portion with less than a predetermined number of pixels in the image obtained by the first scan.

[0124] According to this workpiece height measuring device, the criterion for determining that a portion is a missing portion, which serves as a trigger for executing the second scan, can be arbitrarily set based on the number of pixels.

[0125] In the above-mentioned work height measuring device, the work is mounted on a supporting surface of a substrate, and the measurement unit causes the scan driving unit to execute multiple scans in different orientations of the irradiation direction of the line light, targeting a model substrate on which the work is mounted in a predetermined arrangement on the substrate, and when a work mounted on a substrate in the same arrangement as the model substrate is to be subjected to height measurement, at least a scan to be used as the first scan can be selected from the multiple scans to obtain height data.

[0126] According to this work height measuring device, since multiple scans are performed using a model board, it is possible to detect the optimum scan in which height data loss is least likely to occur. Then, for a mounting board that is the same as the model board, the optimum scan detected in advance can be applied.

[0127] In this case, it is desirable for the measurement unit to identify a data-containing area in the multiple scans where height data higher than the height of the placement surface has been obtained, calculate the area of ​​the missing portion in the height data adjacent to the data-containing area in the scanning direction, and select as the first scan the scan in which the area of ​​the missing portion is smallest from among the multiple scans.

[0128] According to this workpiece height measuring device, the first scan can be performed in a scan mode that minimizes the area in which missing parts of the height data occur.

[0129] In the above-mentioned workpiece height measuring device, it is desirable that the measuring unit performs the first scan on one workpiece and also performs the second scan assuming that there is a missing portion, and combines height data obtained from images obtained in the first scan and the second scan to determine height data for the one workpiece.

[0130] This workpiece height measuring device makes it possible to obtain highly accurate workpiece height data by combining the height data obtained from the two scans.

[0131] In the above-mentioned work height measuring device, the scan drive unit includes a first movement mechanism that moves the imaging unit and the line light projection unit horizontally in a first movement direction, and a second movement mechanism that moves them horizontally in a second movement direction perpendicular to the first movement direction in a horizontal plane, the first movement mechanism includes a first encoder that detects a position in the first movement direction with a predetermined resolution, and the second movement mechanism includes a second encoder that detects a position in the second movement direction with the predetermined resolution, and it is desirable that the imaging unit captures an image of the work in synchronization with position detection signals output by the first encoder and the second encoder during scanning.

[0132] According to this workpiece height measuring device, imaging is performed in synchronization with the position detection signals output by the first and second encoders, so that workpiece height data can be obtained at the same pitch regardless of the scanning direction.

[0133] In the above-mentioned work height measuring device, it is desirable to further include a slider that is movable in the scanning direction, a head that is supported by the slider and holds the imaging unit and the line light projection unit rotatably around the imaging optical axis, and a rotation mechanism that rotates the imaging unit and the line light projection unit together or rotates both individually.

[0134] According to this workpiece height measuring device, the imaging unit and the line light projection unit can be rotated integrally or individually, so that the rotation angle of the imaging area and the irradiation direction of the line light can be freely set.

[0135] In the above-mentioned workpiece height measuring device, a configuration may be adopted in which a plurality of the line light projection units are arranged at a predetermined pitch on a circumference centered on the imaging optical axis of one of the imaging units.

[0136] According to this workpiece height measuring device, the irradiation direction of the line light can be changed by selecting one of the multiple line light projection units arranged in a circumferential array.

[0137] A mounted board inspection apparatus according to another aspect of the present invention includes a measurement stage onto which a mounted board having components mounted thereon is carried, and the above-mentioned work height measurement device that measures the height of the components on the mounted board carried into the measurement stage as the work.

[0138] According to this mounted board inspection device, the component height can be accurately measured regardless of the arrangement of the components, so that accurate mounted board inspection can be performed.

Claims

1. An imaging unit having an imaging optical axis in a vertical direction and capturing an image of a workpiece; a line light projection unit having a projection optical axis having a predetermined intersection angle with the imaging optical axis and capable of irradiating a workpiece with line light from a plurality of directions; a scan driving unit that moves the imaging unit and the line light projection unit to scan a workpiece; A measurement unit that controls the scan driving unit to execute the scan and obtains height data of the workpiece by a light cutting method based on an image acquired by the scan, The measurement unit is A first scan is performed by irradiating the line light onto the workpiece from a predetermined irradiation direction; determining whether or not there is a missing portion in the height data of the workpiece obtained based on the image acquired in the first scan; When the missing portion is detected, a second scan is performed in which the irradiation direction of the line light is oriented in a different direction from the first scan. The measurement unit is When a missing portion of the height data is detected, it is determined whether or not the missing portion is caused by a scanning direction; A workpiece height measuring device that executes the second scan if the missing portion is caused by the scan direction.

2. 2. The workpiece height measuring device according to claim 1, The measurement unit is a first scanning direction is set to a first scanning direction while a posture of an imaging area of ​​the imaging unit and an irradiation direction of the line light are set to predetermined conditions, and the first scanning is performed; A workpiece height measuring device that performs the second scan by rotating the imaging area around the imaging optical axis while maintaining the scanning direction in the first scan direction, and changing the orientation of the irradiation direction of the line light so that the relationship between the irradiation direction of the line light and the posture of the imaging area is maintained the same as in the first scan.

3. 2. The workpiece height measuring device according to claim 1, The measurement unit is a first scanning direction is set to a first scanning direction while a posture of an imaging area of ​​the imaging unit and an irradiation direction of the line light are set to predetermined conditions, and the first scanning is performed; A workpiece height measuring device which sets a scan direction to a second scan direction different from the first scan direction, rotates the imaging area around the imaging optical axis in accordance with the second scan direction, and changes the orientation of the irradiation direction of the line light so that the relationship between the irradiation direction of the line light and the posture of the imaging area is maintained the same as in the first scan, thereby executing the second scan.

4. 2. The workpiece height measuring device according to claim 1, the scan driving unit includes a first moving mechanism that horizontally moves the imaging unit and the line light projection unit in a first moving direction, and a second moving mechanism that horizontally moves the imaging unit and the line light projection unit in a second moving direction perpendicular to the first moving direction in a horizontal plane, A workpiece height measuring device, wherein the measurement unit selects and operates either the first movement mechanism or the second movement mechanism when performing the first scan and the second scan.

5. In the workpiece height measuring device according to claim 4, A workpiece height measuring device, wherein the measurement unit selects the first moving mechanism or the second moving mechanism, the one having a shorter scan distance.

6. In the work height measuring device according to any one of claims 1 to 5, The workpiece is a substrate on which a plurality of components are mounted, The measurement unit acquires component mounting data including information regarding the shape of the component and its mounting position on the board, and determines whether or not there are any missing parts in the height data based on the component mounting data.

7. In the work height measuring device according to claim 1, The workpiece is mounted on a mounting surface of a substrate, The measurement unit is Identifying a data-available region in which height data higher than the height of the placement surface is obtained; A workpiece height measuring device that executes the second scan when the missing portion is adjacent to the data-containing area in the scanning direction.

8. In the work height measuring device according to claim 7, A work height measuring device, wherein the measurement unit performs the second scan when the missing portion adjacent to the data-containing area in the scanning direction is a missing portion having less than a predetermined number of pixels in the image obtained by the first scan.

9. An imaging unit having an imaging optical axis in a vertical direction and capturing an image of a workpiece; a line light projection unit having a projection optical axis having a predetermined intersection angle with the imaging optical axis and capable of irradiating a workpiece with line light from a plurality of directions; a scan driving unit that moves the imaging unit and the line light projection unit to scan a workpiece; A measurement unit that controls the scan driving unit to execute the scan and obtains height data of the workpiece by a light cutting method based on an image acquired by the scan, The measurement unit is A first scan is performed by irradiating the line light onto the workpiece from a predetermined irradiation direction; determining whether or not there is a missing portion in the height data of the workpiece obtained based on the image acquired in the first scan; When the missing portion is detected, a second scan is performed in which the irradiation direction of the line light is oriented in a different direction from the first scan. The workpiece is mounted on a mounting surface of a substrate, The measurement unit is a model board on which the workpiece is mounted in a predetermined arrangement is subjected to a plurality of scans in which the scanning driving unit is caused to irradiate the line light in different orientations; A work height measurement device, in which when the height measurement is to be performed on a work mounted on a substrate in the same arrangement as the model substrate, at least a scan to be used as the first scan is selected from the multiple scans to obtain height data.

10. In the work height measuring device according to claim 9, The measurement unit is Identifying a data-present area in which height data higher than the height of the placement surface is obtained in the plurality of scans; An area of ​​a missing portion of the height data adjacent to the data-containing region in a scanning direction is calculated; A workpiece height measuring device that selects, from the plurality of scans, the scan in which the area of ​​the missing portion is smallest as the first scan.

11. An imaging unit having an imaging optical axis in a vertical direction and capturing an image of a workpiece; a line light projection unit having a projection optical axis having a predetermined intersection angle with the imaging optical axis and capable of irradiating a workpiece with line light from a plurality of directions; a scan driving unit that moves the imaging unit and the line light projection unit to scan a workpiece; A measurement unit that controls the scan driving unit to execute the scan and obtains height data of the workpiece by a light cutting method based on an image acquired by the scan, The measurement unit is A first scan is performed by irradiating the line light onto the workpiece from a predetermined irradiation direction; determining whether or not there is a missing portion in the height data of the workpiece obtained based on the image acquired in the first scan; When the missing portion is detected, a second scan is performed in which the irradiation direction of the line light is oriented in a different direction from the first scan. The measurement unit is The first scan is performed for one workpiece, and the second scan is performed assuming that the missing portion is present; A workpiece height measuring device that determines height data for one workpiece by combining height data obtained from the images obtained in the first scan and the second scan.

12. 2. The workpiece height measuring device according to claim 1, the scan driving unit includes a first moving mechanism that horizontally moves the imaging unit and the line light projection unit in a first moving direction, and a second moving mechanism that horizontally moves the imaging unit and the line light projection unit in a second moving direction perpendicular to the first moving direction in a horizontal plane, the first movement mechanism includes a first encoder that detects a position in the first movement direction with a predetermined resolution, and the second movement mechanism includes a second encoder that detects a position in the second movement direction with the predetermined resolution, A workpiece height measuring device, wherein the imaging unit captures an image of the workpiece in synchronization with position detection signals output by the first encoder and the second encoder during scanning.

13. The work height measuring device according to any one of claims 1 to 12, a slider movable in a scanning direction; a head supported by the slider and configured to rotatably hold the imaging unit and the line light projection unit around the imaging optical axis; The workpiece height measuring device further includes a rotation mechanism that rotates the imaging unit and the line light projection unit together or rotates both of them individually.

14. The work height measuring device according to any one of claims 1 to 12, A workpiece height measuring device, in which a plurality of the line light projection units are arranged at a predetermined pitch on a circumference centered on the imaging optical axis of one of the imaging units.

15. a measurement stage onto which a mounting board on which components are mounted is carried; The workpiece height measuring device according to any one of claims 1 to 14, which measures the height of a component on the mounting board that is carried into the measurement stage as the workpiece; A mounting board inspection device comprising:

Images