CN117881941A - Workpiece height measuring device and mounting substrate inspection device using the same - Google Patents

Abstract

The workpiece height measuring device includes: a photographing section photographing an image of a workpiece; a line light projection unit having a projection optical axis with a predetermined intersection angle with respect to the imaging optical axis, capable of irradiating the workpiece with line light from a plurality of directions; a scanning drive unit that moves the imaging unit and the line light projection unit and scans a workpiece; and a measuring unit for obtaining height data of the workpiece by a light cutting method based on the image obtained by the scanning. The measurement unit irradiates the line light to a workpiece from a predetermined irradiation direction to cause the 1 st scan to be executed, the measurement unit determines whether or not a missing portion of the height data of the workpiece exists in the height data obtained from the image acquired by the 1 st scan, and the measurement unit causes the irradiation direction of the line light to be set to a 2 nd scan of a different azimuth from the 1 st scan to be executed when the missing portion is detected.

Description

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

Technical Field

The present invention relates to a height measuring device for a workpiece such as an electronic component mounted on a substrate, and a mounted substrate inspection device using the same.

Background

For example, in a component mounting substrate production line in which an electronic component (workpiece) is mounted on a substrate, it is necessary to check whether or not the electronic component is mounted on the substrate as designed. If the height measurement is performed on the component mounting substrate, mounting defects of the electronic component such as component bumps, mounting position shifts, missing mounting, and the like can be detected. As a method for measuring the height of a workpiece in a noncontact manner, a photocutting method is known. In the case of using the optical cutting method, a workpiece to which line light is obliquely irradiated is photographed, and the height of the workpiece is obtained from the photographed image by using the principle of triangulation. Patent document 1 discloses a three-dimensional shape measuring device for a workpiece using a light cutting method. The device of patent document 1 includes a mechanism for rotating a light cutting probe having a line light source and a camera.

When measuring the height of a workpiece, scanning is performed in which imaging is performed a plurality of times while horizontally moving a line light source and a camera with respect to the workpiece. By calculating height data from the respective images obtained by scanning and synthesizing these height data, the shape of the workpiece can be measured. Here, for example, when a plurality of workpieces are arranged at a high density or a low-height workpiece is arranged adjacent to a high-height workpiece, line light that is to be irradiated to the target workpiece may be blocked by the adjacent workpieces. In this case, there is a problem that the height measurement of the target workpiece cannot be performed accurately.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2015-72197

Disclosure of Invention

The invention aims to provide a workpiece height measuring device capable of accurately measuring the height of a workpiece regardless of the arrangement state of the workpiece and a mounting substrate inspection device using the device.

A workpiece height measuring apparatus according to an aspect of the present invention includes: a photographing section having an imaging optical axis in a plumb direction and photographing an image of a workpiece; a line light projection unit having a projection optical axis with a predetermined intersection angle with respect to the imaging optical axis, the line light projection unit being capable of irradiating a workpiece with line light from a plurality of directions; a scanning drive unit that moves the imaging unit and the line light projection unit and scans a workpiece; and a measuring unit that controls the scanning driving unit to perform the scanning, and obtains height data of the workpiece by a light-cutting method based on an image obtained by the scanning; the measurement unit irradiates the line light to a workpiece from a predetermined irradiation direction to cause the 1 st scan to be executed, the measurement unit determines whether or not a missing part of the height data of the workpiece exists in the height data obtained from the image obtained by the 1 st scan, and the measurement unit causes the irradiation direction of the line light to be executed in a 2 nd scan having a different azimuth from the 1 st scan when the missing part is detected.

Another aspect of the present invention relates to a mounting board inspection apparatus including: an inspection stage for carrying in the mounting substrate with the components mounted thereon; and the workpiece height measuring device measures the height of the workpiece by using the element carried into the mounting board of the inspection stage as the workpiece.

Drawings

Fig. 1 is a block diagram showing a configuration of a mounting substrate production line in which a workpiece height measuring device according to the present invention is incorporated as an appearance inspection machine.

Fig. 2 (a) to (C) are schematic diagrams showing a method of measuring the element height based on the optical cutting method.

Fig. 3 (a) and (B) are diagrams illustrating the drawbacks of the element height measurement by the optical cutting method, and fig. 3 (C) is a diagram showing the solution thereof.

Fig. 4 is a perspective view schematically showing the hardware configuration of the visual inspection machine.

Fig. 5 is a block diagram showing an electrical structure of the visual inspection machine.

Fig. 6 (a) to (C) are perspective views showing a rotation state of a head portion including a camera unit and a linear light source.

Fig. 7 is a perspective view showing a head according to a modification.

Fig. 8 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 1.

Fig. 9 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 1.

Fig. 10 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 2.

Fig. 11 (a) to (C) are schematic diagrams for explaining measurement of the element height according to embodiment 2.

Fig. 12 is a flowchart showing a scanning direction determination process in element height measurement according to embodiment 2.

Fig. 13 (a) to (E) are schematic diagrams for explaining measurement of the element height according to embodiment 3.

Fig. 14 (a) and (B) are schematic diagrams for explaining measurement of element height according to embodiment 4.

Fig. 15 (a) and (B) are schematic diagrams for explaining measurement of element height according to embodiment 4.

Fig. 16 is a flowchart showing a scanning area determination process in element height measurement according to embodiment 4.

Fig. 17 (a) to (C) are schematic diagrams for explaining measurement of the element height according to embodiment 5.

Fig. 18 (a) to (C) are schematic diagrams for explaining measurement of the element height according to embodiment 5.

Fig. 19 is a flowchart showing a scanning direction determination process for each element in element height measurement according to embodiment 5.

Fig. 20 (a) to (C) are schematic diagrams for explaining measurement of element heights according to a modification of embodiment 5.

Fig. 21 is a flowchart showing a scanning direction determination process for each element in element height measurement according to a modification of embodiment 5.

Fig. 22 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 6.

Fig. 23 is a flowchart showing a process of generating high-precision element height data in element height measurement according to embodiment 6.

Fig. 24 (a) and (B) are diagrams showing a modification of scanning.

Fig. 25 is a diagram showing a modification of acquiring image data.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The workpiece height measuring device according to the present invention can be widely applied to shape measurement of various industrial products, semi-finished products, machine parts, electronic components, food, agricultural products, and other workpieces. In the embodiment shown below, an example in which height measurement is performed using an element mounted on a substrate as a workpiece will be described. Here, an example in which the workpiece height measuring device according to the present invention is applied to the appearance inspection of a substrate after component mounting in a production line for mounting the substrate is shown.

[ mounting substrate production line ]

Fig. 1 is a block diagram showing a configuration of a mounting board production line 1 for mounting electronic components on a printed board. The mounting substrate production line 1 includes a printer 11, a printing inspection machine 12, a component mounting machine 13, a reflow oven 14, and an appearance inspection machine 15 (workpiece height measuring device/mounting substrate inspection device) arranged in this order from the upstream side to the downstream side in the substrate conveyance direction.

The printer 11 applies solder to the land portion of the printed board. For example, the printer 11 superimposes the printed substrate on a mask of the solder application portion opening, and applies paste solder from above the mask. The printing inspection machine 12 inspects whether the position or amount of the solder coated on the printed substrate is proper. The component mounter 13 includes a head for mounting components, and mounts necessary components on a printed board. The reflow oven 14 heats the printed board on which the components are mounted to melt the solder, thereby fixing the components to the board.

The appearance inspection machine 15 inspects whether or not the electronic component is mounted in a correct position on the printed substrate without defects. Specifically, the appearance inspection machine 15 inspects positional displacement of electronic components mounted on the printed board, component bumps, missing mounting, soldering defects, and the like. These inspections are performed by performing an appearance inspection of the mounting substrate, that is, performing a height measurement of the mounting substrate. The appearance inspection machine 15 detects mounting failure by collating the height data obtained by the height measurement with the design data of the substrate. The appearance inspection machine 15 of the present embodiment performs the height measurement by using a light cutting method.

[ altitude measurement by light-cutting method ]

The height measurement by the light cutting method using the appearance inspection machine 15 will be described with reference to fig. 2 (a) to (C). As shown in fig. 2 a, the measurement object is an element C (workpiece) mounted on the substrate surface PS of the mounting substrate P. The appearance inspection machine 15 includes a camera unit 4 (imaging unit) and a line light source 5 (line light projection unit), and the hardware configuration thereof will be described later.

The camera unit 4 has an imaging optical axis AX in a plumb direction with respect to the substrate surface PS, and captures an image of the element C. The line light source 5 has a projection optical axis having a predetermined intersection angle θ with respect to the imaging optical axis AX, and emits line light SL along the projection optical axis. The line light SL is irradiated to the element C of the measurement object. In the present embodiment, the unit mounted with the camera unit 4 and the line light source 5 includes a mechanism that rotates around the axis of the imaging optical axis AX. With this mechanism, the line light source 5 can irradiate the element C to be measured with the line light SL from a plurality of directions.

Fig. 2 (B) shows an image IM acquired by the camera unit 4 at a certain scanning position SC1, with the line light SL being irradiated to the element C. When the line light SL is irradiated to the region including the element C, the reflected light RL1 from the substrate surface PS around the element C and the reflected light RL2 from the upper surface of the element C are captured by the camera unit 4. Since the line light SL is oblique light and the element C has a height, reflected light RL1, RL2 is observed at different positions of the X-coordinate on the image IM. Specifically, the reflected light RL1 is present at a coordinate x11, and the reflected light RL2 is present at a coordinate x12 located on the downstream side in the scanning direction with respect to the coordinate x 11.

The case where the line light SL is irradiated to the point P0 of (a) of fig. 2 is regarded as a place of the calculated height=0. Then, as shown in fig. 2 (C), based on the principle of triangulation using the intersection angle θ, height data of the height h1 of the coordinate x11 and the height h2 of the coordinate x12 can be obtained. After that, when the camera unit 4 and the line light source 5 are moved from the scanning position SC1 to the scanning direction downstream side, the scanning positions SC2 and SC3 are imaged sequentially by the camera unit 4. Thereby, height data of coordinates x21, x22 at the scanning position SC2 and height data of coordinates x31, x32 at the scanning position SC3 are acquired. Of course, the actual scan pitch is much narrower than the illustrated example.

By integrating a plurality of height data acquired by scanning, three-dimensional shape data of the element C can be obtained. Further, the height data acquired at one scanning position SC1, SC2, SC3 is based on the result of the reflected light RL1, RL2 being irradiated at different X-coordinate positions. Thus, at the time of data integration, for example, a height table integrating height data of the coordinate x12 obtained at the scanning position SC1 in the region of the element C with height data of the coordinate x12 obtained at the scanning position thereafter in the region of the substrate surface PS is generated.

Fig. 3 (a) and (B) are diagrams illustrating the drawbacks of the element height measurement based on the optical cutting method. The projection optical axis of the line light SL generated by the line light source 5 is inclined with respect to the plumb axis. Therefore, as shown in fig. 3 (a), when the line light SL irradiates the element C having a height, a shadow portion SH is generated which becomes a shadow of the element C and is not irradiated with the line light SL. In the area of the shadow SH, the reflected light having a predetermined brightness is not incident on the camera unit 4, and thus the height measurement cannot be performed. Fig. 3 (B) is a diagram showing the measurement result of the height data of the mounting substrate P shown in fig. 3 (a). Although the heights of the element C and the substrate surface PS can be measured, the area of the hatched portion SH becomes a deficient portion of the height data.

Fig. 3 (C) is a diagram showing a solution for preventing the occurrence of the height data deficiency. As the line light source 5, a 1 st line light source 5A and a 2 nd line light source 5B arranged to face each other in the scanning direction F are used. The 1 st line light source 5A irradiates the 1 st line light SL1 toward the substrate surface PS at a predetermined intersection angle θ. The 2 nd line light source 5B is disposed in the opposite direction to the 1 st line light source 5A across the imaging optical axis AX. The 2 nd line light source 5B irradiates the 2 nd line light SL2 toward the substrate surface PS from a direction 180 degrees different from the 1 st line light SL at the same intersection angle θ as the 1 st line light SL1.

If the 2 nd line light SL2 is used, the shadow portion SH can be illuminated. By combining the height measurement result obtained by using the 1 st line light SL1 and the height measurement result obtained by using the 2 nd line light SL2, the missing portion of the height data can be eliminated. However, even when the pair of linear light sources 5A and 5B are used, a missing portion of the height data may be generated. In the present embodiment, the height measurement can be performed for the height data missing portion that cannot be eliminated even when the pair of line light sources 5A, 5B is used.

[ description of the device configuration ]

Fig. 4 is a perspective view schematically showing the hardware configuration of the appearance inspection machine 15, and fig. 5 is a block diagram showing the electrical configuration of the appearance inspection machine 15. The appearance inspection machine 15 includes a measuring device main body 2, a control device 3 (measuring unit), and a server device 30. The measuring device main body 2 performs a height measuring operation of the mounting substrate P. The measuring device main body 2 includes a base 21, a moving beam 22, a Y-axis moving mechanism 23 (scanning drive unit/No. 2 moving mechanism), an X-axis moving mechanism 24 (scanning drive unit/No. 1 moving mechanism), a slider 25, and a head 25H. The camera unit 4 and the line light source 5 are mounted on the head 25H.

The base 21 is a flat plate-shaped frame that supports the Y-axis moving mechanism 23 and becomes a measurement table 21S on which the substrate P is mounted. The mounting board P to be inspected for appearance is carried in from the reflow oven 14 to the measuring table 21S by a conveyor, not shown, and the mounting board P is carried out after inspection. The moving beam 22 is a gate-shaped skeleton extending in the X direction, and moves in the Y direction above the base 21. The moving beam 22 holds the head 25H via the slider 25.

The Y-axis moving mechanism 23 and the X-axis moving mechanism 24 function as a scanning drive unit that moves the camera unit 4 and the line light source 5 and scans the element C (workpiece). The Y-axis moving mechanism 23 is a mechanism that is disposed at both ends of the base 21 in the X-direction in a pair and horizontally moves the moving beam 22 holding the head 25H (the camera unit 4 and the line light source 5) in the Y-direction (the 2 nd moving direction orthogonal to the 1 st moving direction in the horizontal plane). The Y-axis moving mechanism 23 includes a Y-axis motor 231 configured by 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 to a ball nut assembled to the traveling beam 22. The X-axis moving mechanism 24 is a mechanism provided on the moving beam 22 and horizontally moves the head 25H in the X direction (1 st 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.

The slider 25 is a plate material holding the head 25H, and is assembled to the movable beam 22 so as to be movable in the X direction (scanning direction). The X-axis ball screw shaft is screwed to a ball nut assembled to the slider 25. The slider 25 moves in the X direction along the moving beam 22 by rotationally driving the X-axis ball screw shaft by the X-axis motor 241. On the other hand, the moving beam 22 moves in the Y direction by rotationally driving the Y-axis ball screw shaft by the Y-axis motor 231. Therefore, the head 25H held by the slider 25 is movable in the XY direction based on the Y-axis movement mechanism 23 and the X-axis movement mechanism 24.

The head 25H includes: a camera unit 4 and a pair of line light sources 5 (1 st line light source 5A and 2 nd line light source 5B) for measuring the height of the element C; a support plate 251; a light source holder 51; and a rotation mechanism 6. The support plate 251 is a plate extending from the slider 25 in the Y direction, and rotatably supports the camera unit 4 and the line light source 5 about the imaging optical axis AX. The light source holder 51 is a blade-type support beam integrated with the camera unit 4, and supports the 1 st line light source 5A by one blade and the 2 nd line light source 5B by the other blade. The rotation mechanism 6 is a mechanism that is mounted on the support plate 251 and integrally rotates the camera unit 4 and the line light source 5 around the imaging optical axis AX. The rotation mechanism 6 may be a mechanism that rotates the camera unit 4 and the light source holder 51 that holds the line light source 5 independently.

The control device 3 controls various operations of the measuring device body 2. Specifically, the control device 3 controls the Y-axis moving mechanism 23 and the X-axis moving mechanism 24 to cause the head 25H to perform scanning of the mounting board P, and obtains the height data of the component C mounted on the mounting board P by a light-cutting method from an image obtained by the scanning. The server device 30 relays data transfer between the control device 3 and the measuring device main body 2.

The electrical structure of the appearance inspection machine 15 will be described with reference to fig. 5. In fig. 5, the description of the server apparatus 30 is omitted. The measuring device main body 2 includes a Z-axis motor 261 and an R-axis motor 61, which are elements not shown in fig. 4. The Z-axis motor 261 is a driving source for moving the head 25H up and down in the Z-axis direction. The Z-axis motor 261 lifts and lowers the head 25H as needed when there is a large warp in the mounting substrate P to be measured. In addition, the Z-axis motor 261 may be omitted in the case where it is not necessary to assume that the mounting substrate P is greatly warped. 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.

The camera unit 4 includes a camera body 41 including an imaging device such as a CMOS sensor, an imaging lens 42 for making an optical image of the mounting substrate P incident on the camera unit 4, and a body 43 incorporating an optical system for imaging the optical image on an imaging surface of the imaging device. The light source holder 51 is mounted to the body portion 43. The rotation mechanism 6 is also mounted to the body portion 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 linear light sources 5A and 5B attached to the light source holder 51 also rotate.

Fig. 6 (a) to (C) are perspective views showing a rotation state of the head 25H. Fig. 6 (a) shows a state in which the rotation angle of the head 25 h=0 degrees. In this state, the pair of line light sources 5A, 5B are arranged along the X direction. The line light SL emitted from each of the line light sources 5A and 5B becomes line light extending in the Y direction. Fig. 6 (B) shows a state in which the rotation angle of the head 25 h=45 degrees. In this case, the line light sources 5A and 5B are arranged on a line inclined at 45 degrees with respect to both the X direction and the Y direction, and the line light SL is also 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 in which the rotation angle of the head 25 h=90 degrees. In this state, the pair of line light sources 5A, 5B are arranged along the Y direction, and the line light SL becomes line light extending along the X direction. In this way, by rotating the head 25H by the rotation mechanism 6, the irradiation direction of the line light SL can be set to a desired direction.

A Y-axis encoder 232 (2 nd encoder), an X-axis encoder 242 (1 st encoder), a Z-axis encoder 262, and an R-axis encoder 62 are attached to the Y-axis motor 231, the X-axis motor 241, the Z-axis motor 261, and the R-axis motor 61, respectively. The Y-axis encoder 232 outputs a position detection signal for detecting the Y-direction position of the movable beam 22 (head 25H) at a predetermined resolution. The X-axis encoder 242 outputs a position detection signal for detecting the X-direction position of the head 25H at a predetermined resolution. The Z-axis encoder 262 outputs a position detection signal indicating the Z-direction position of the head 25H. The R-axis encoder 62 outputs a position detection signal indicating the rotational position of the head 25H.

The control device 3 includes a microcomputer or the like, and executes a predetermined program to operate so as to functionally include a photographing control unit 31, a scanning control unit 32, a measurement processing unit 33, and an installation data storage unit 34. The position detection signals are input to the control device 3 from each of the X-axis, Y-axis, Z-axis, and R-axis encoders 232, 242, 262, and 62 via the server device 30.

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 issues an imaging instruction to cause the camera unit 4 to perform an imaging operation at a predetermined timing when the line light source 5 emits the line light SL, and receives image data obtained by the imaging as measurement data. The imaging control unit 31 scans the element C by causing the camera unit 4 to perform imaging of the element C in synchronization with the position detection signals output from the Y-axis encoder 232 and the X-axis encoder 242 as the head 25H moves. For example, the imaging control unit 31 issues the imaging command every time the position detection signal reaches a predetermined count number. This makes it possible to set the scanning distance and the scanning direction dimension on the image data to an arbitrary proportional relationship. As a result, the height data of the element C can be acquired at the same pitch regardless of which direction the scanning direction is.

The scan control unit 32 controls the Y-axis motor 231 and the X-axis motor 241, and moves the head 25H on which the camera unit 4 and the line light source 5 are mounted in a desired scan direction by the Y-axis movement mechanism 23 and the X-axis movement mechanism 24. The scanning control unit 32 operates the Z-axis motor 261 as necessary to adjust the height of the head 25H. The scan control unit 32 controls the R-axis motor 61 to rotate the head 25H so as to set the irradiation direction of the line light SL from the line light source 5 to a desired azimuth.

The measurement processing unit 33 performs arithmetic processing for obtaining the height data of the element C by the optical cutting method based on the image acquired by the camera unit 4 at the time of the scanning. For example, the measurement processing unit 33 detects the reflected lights RL1 and RL2 as illustrated in fig. 2 (B) by an image processing method such as an edge detection process. The measurement processing unit 33 also performs processing for detecting the presence or absence of a missing portion of the height data. The missing portion corresponds to a position where the height data cannot be measured due to, for example, an influence of the hatched portion SH shown in fig. 3 (a). Assume that: the missing portion is detected in height data obtained by performing scanning (1 st scanning) in a certain scanning direction/irradiation direction of the line light SL and from an image acquired by the scanning. In this case, the measurement processing unit 33 causes the imaging control unit 31 and the scanning control unit 32 to perform rescanning (2 nd scan) in which the scanning direction and the irradiation direction of the line light SL are different.

The mounting data storage section 34 stores mounting data about the mounting substrate P. The mounting data includes, for example, the type, XY size, height, number, arrangement position on the substrate, and the like of the component C. In some embodiments described later, the installation data stored in the installation data storage unit 34 is used.

Fig. 7 is a perspective view showing a head 25HA according to a modification. Fig. 4 shows an example in which the irradiation direction of the line light SL is changed by rotating the head 25H around the imaging optical axis AX by the rotation mechanism 6. In fig. 7, the head 25HA of the rotation mechanism 6 may be omitted. The head 25HA is formed by arranging a plurality of line light sources 5 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 10 line light sources 5a1, 5a2, 5b1, 5b2, 5c1, 5c2, 5d1, 5d2, 5e1, 5e2 are arranged at equal intervals on the circumference. By selecting a group of the 10 line light sources 5a1 to 5e2, for example, the line light sources 5a1, 5a2 or the line light sources 5b1, 5b2, which are arranged opposite to each other across the imaging optical axis AX and are paired, the irradiation direction of the line light SL can be changed.

[ embodiment 1 of height measurement ]

Fig. 8 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 1. In embodiment 1, an example is shown in which the 1 st scan is performed with the irradiation direction of the line light SL as a default set azimuth, and then the head 25H is rotated so that the irradiation direction of the line light SL becomes a different azimuth, and the 2 nd scan is performed. In fig. 8 and the following drawings, for simplifying the drawings, the head 25H is shown by simplifying the drawings by a camera unit 4 shown by a substantially square shape and a pair of linear light sources 5A, 5B shown by an elongated rectangle shape arranged across the camera unit 4. Schematically showing the pose of the imaging range of the camera unit 4 and the irradiation directions of the line lights SL1, SL2 emitted from the line light sources 5A, 5B.

Fig. 8 (a) shows the state of the 1 st scan. The object of the height measurement is a mounting substrate P on which a tall element C1 having a higher head and a short element C2 having a shorter head are mounted. Short component C2 is mounted in the area surrounded by tall component C1. When scanning 1, the scanning control unit 32 operates the Y-axis motor 231 and/or the X-axis motor 241 with the rotational position of the head 25H as a default setting position. Thereby, the head 25H is moved in the predetermined scanning direction F. The imaging control unit 31 causes the camera unit 4 to perform an imaging operation when the 1 st line light SL1 or the 2 nd line light SL2 is emitted from the 1 st line light source 5A or the 2 nd line light source 5B. The same applies to the 2 nd scan performed thereafter.

In the 1 st scan, the scanning direction F is the X direction (1 st scan direction), and the facing direction of the pair of line light sources 5A, 5B is also the X direction. That is, the projection optical axis of the 1 st line light SL1 or the 2 nd line light SL2 is a direction following the X direction, and the direction in which the 1 st line light SL1 or the 2 nd line light SL2 projected on the measurement object extends is the Y direction orthogonal to the scanning direction F. As is clear from fig. 8 (a), when the scanning direction F is the X direction, a region in which the short element C2 is spaced between the 2 tall elements C1 arranged in the X direction is scanned. The measurement processing unit 33 performs processing for obtaining height data of the tall element C1 and the short element C2 based on the optical cut method based on the image obtained by the 1 st scan.

Fig. 8 (B) is a diagram showing the irradiation state of the 1 st line light SL1 or the 2 nd line light SL2 in the case of performing the 1 st scan in the scanning direction F and the line light projection direction of fig. 8 (a). The 1 st line light SL1 emitted from the 1 st line light source 5A is blocked by the tall element C1 on the left side in the figure, and cannot be irradiated to the short element C2. The 2 nd line light SL2 emitted from the 2 nd line light source 5B is blocked by the tall element C1 on the right side in the figure, and cannot be irradiated to the short element C2.

In the case where the tall element C1 is present only on one side of the short element C2, as shown in fig. 3 (B), one of the 1 st line light SL1 and the 2 nd line light SL2 can be irradiated to the short element C2. However, if the tall element C1 is present on both sides of the short element C2, both the 1 st line light SL1 and the 2 nd line light SL2 may not be irradiated to the short element C2. In this case, since the reflected light from the short element C2 is not incident on the camera unit 4, the measurement processing section 33 cannot obtain the height data on the mounting region of the short element C2. In this case, the measurement processing unit 33 determines that the height data deficiency portion is "present" in the height measurement based on the 1 st scan.

When the height data deficiency is detected, the measurement processing unit 33 sets at least the irradiation directions of the line lights SL1 and SL2 to different orientations, and causes the 2 nd scan to be executed. Fig. 8 (C) is a diagram showing example 1 of the 2 nd scan. In this example 1, the scanning direction F is maintained in the same X direction as the 1 st scanning direction, and the head 25H is rotated by about 45 degrees. Although short element C2 is sandwiched between tall elements C1 when viewed from the X direction and the Y direction, it is in a positional relationship not sandwiched between tall elements C1 when viewed from the direction intermediate between the X direction and the Y direction.

The imaging range of the camera unit 4 is also set to a posture rotated by about 45 degrees around the imaging optical axis AX by the rotation of the head 25H. The irradiation directions (projection optical axes) of the line lights SL1, SL2 also rotate around the imaging optical axis AX. That is, the relationship between the irradiation directions of the line lights SL1, SL2 and the posture of the imaging range is maintained to be the same as the 1 st scan. The extending directions of the line lights SL1 and SL2 are inclined by about 45 degrees with respect to the X direction. By setting such an irradiation direction to perform the 2 nd scan, either the 1 st line light SL1 or the 2 nd line light SL2 can irradiate the short element C2. Therefore, the measurement processing unit 33 can determine the height data of the short element C2, which was the missing part of the height data, from the image acquired by the 2 nd scan. In the 1 st and 2 nd scans, the relationship between the posture of the imaging range and the irradiation directions of the line lights SL1 and SL2 is maintained to be the same, so that the height data can be efficiently derived.

Fig. 8 (D) is a diagram showing example 2 of the 2 nd scan. In this example 2, an example is shown in which the scanning direction F is set to a direction different from the scanning direction 1 to perform the scanning direction 2. The scanning direction F of the 2 nd scan is a direction inclined by about 45 degrees with respect to the X direction which is the scanning direction F (the 2 nd scan direction). As in example 1, the head 25H is rotated, and the imaging range of the camera unit 4 and the irradiation directions of the line lights SL1 and SL2 are also rotated by about 45 degrees with respect to the setting of the 1 st scan. In example 2, the relationship in which the scanning direction F is orthogonal to the extending direction of the line light SL1, SL2 is maintained in both the 1 st scanning and the 2 nd scanning. Even in the case of example 2, the height data of the short element C2, which was a missing part of the height data, can be obtained by irradiating the short element C2 with one of the 1 st line light SL1 and the 2 nd line light SL2 by the 2 nd scan.

Fig. 9 (a) to (D) are schematic diagrams for explaining other examples of the missing portion generating the height data and an element height measurement example in this case. As shown in fig. 9 (a), in the actual mounting board P, the components C may be mounted at a narrow inter-component pitch W. In such a mounting board P, if the array direction of the elements C is scanned in the scanning direction F, height data between the elements C may not be acquired.

Referring to fig. 9 (B), if 2 elements C are arranged on the mounting substrate P at a narrow inter-element pitch W along the scanning direction F, a region where neither the 1 st line light SL1 nor the 2 nd line light SL2 can reach the substrate surface PS is generated. When the line lights SL1, SL2 are irradiated toward the substrate surface PS at the intersection angle θ (fig. 2), the line lights SL1, SL2 are blocked by the element C when the height of the element C is set to H and the inter-element pitch W is w=h/tan θ or less. In this case, a missing portion of the height data is generated in the region of the inter-element pitch W.

Fig. 9 (C) and (D) show examples of height measurement of the mounting board P including the arrangement of the element C described above. Here, the mounting substrate P in which the plurality of elements C are arranged in a matrix in the XY direction at a narrow pitch is exemplified. In the 1 st scan shown in fig. 9C, the scan direction F is set to the X direction (1 st scan direction). The opposite direction of the pair of line light sources 5A, 5B is also the X direction. On the other hand, the extending direction of the 1 st line light SL1 and the 2 nd line light SL2 projected onto the substrate surface PS is the Y direction. In this 1 st scan, the region of the pitch Wx of the elements C arranged in the X direction may become a missing portion of the height data, but the region of the pitch Wy of the elements C arranged in the Y direction can acquire the height data.

Fig. 9 (D) shows the condition of the 2 nd scan. The scanning direction F of the 2 nd scan is set to the Y direction rotated 90 degrees from the X direction. That is, the head 25H is rotated by 90 degrees. Thus, the imaging range of the camera unit 4 is rotated by about 90 degrees around the imaging optical axis AX with respect to the 1 st scan, and the irradiation directions of the line lights SL1 and SL2 are also rotated by 90 degrees around the imaging optical axis AX. In the 2 nd scan, the region of the pitch Wy of the elements C arranged in the Y direction may become a missing part of the height data. However, in the 1 st scan, the height data can be acquired for the region of the pitch Wx of the elements C arranged in the X direction, which becomes the height data deficiency. Therefore, by combining the measurement results of the 1 st scan and the 2 nd scan, the height data deficiency can be eliminated.

[ embodiment 2 ]

In embodiment 2, an example is shown in which the scanning direction F is limited to one of the X direction and the Y direction in order to simplify the movement control of the head 25H. That is, the control device 3 selects one of the Y-axis moving mechanism 23 and the X-axis moving mechanism 24 to operate when the 1 st scan and the 2 nd scan are executed. In making the selection, reference is made to a scannable width, a scanning distance, or the like.

In the height measurement using the mounting board P or the like as the measurement target, the head 25H must be moved in order to irradiate the entire area of the measurement target with the radiation light SL. At this time, if the Y-axis moving mechanism 23 and the X-axis moving mechanism 24 are operated simultaneously, the scanning direction F can be set in all directions. For example, the scanning direction F can be set to be the intermediate direction between the X direction and the Y direction as illustrated in fig. 8 (D). However, in this case, the scanning control unit 32 must control the Y-axis motor 231 and the X-axis motor 241 in synchronization, and the driving control becomes complicated. In order to simplify the driving control, it is preferable to perform control to operate only one of the Y-axis motor 231 and the X-axis motor 241 during scanning. In addition, it is preferable that whether or not the time required for scanning the entire region of the measurement object in one direction is short is used as a judgment factor in terms of how one of the X direction and the Y direction is selected as the scanning direction F.

As described with reference to fig. 3 (C), in order to avoid the influence of the shadow portion SH of the element C, it is necessary to scan both of the 2 lines SL1 and SL2 so as to pass through the measurement object. However, the scannable width may be made different in width in the X-direction and the Y-direction based on the rotation angle of the head 25H. In this regard, description will be given with reference to fig. 10 (a) to (D). Fig. 10 shows an imaging range 4A of the camera unit 4 and line lights SL1 and SL2 projected into the imaging range 4A.

Fig. 10 (a) shows a state in which the rotation angle of the head 25 h=0 degrees. In the state of 0 degrees, the line lights SL1, SL2 extend in the Y direction. Therefore, in the X-direction scanning in which the X-direction is selected as the scanning direction F, the scannable width X thereof is the maximum width max. On the other hand, in the Y-direction scanning in which the Y-direction is selected as the scanning direction F, the scannable width Y is zero and cannot be measured.

Fig. 10 (B) shows a state in which the rotation angle of the head 25H is=30 degrees. In the state of 30 degrees, the area where both of the 2 line lights SL1, SL2 can be irradiated is narrower than the state of 0 degrees in the X-direction scanning. Therefore, the scannable width X is x=x1 smaller than the maximum width max. On the other hand, in the Y-direction scanning, the area where both of the 2 line lights SL1 and SL2 can be irradiated is not zero, and the scannable width y=y1 is obtained. But y1< x1. Fig. 10 (C) shows a state in which the rotation angle of the head 25 h=60 degrees. In the 60-degree state, since the extending direction of the line light SL1, SL2 approaches the Y direction, the scannable width Y in the Y direction increases and the scannable width X in the X direction decreases. That is, the scannable width x=x2, and the scannable width y=y2 are in a relationship of Y2> X2.

Fig. 10 (D) shows a state in which the rotation angle of the head 25 h=90 degrees. In the state of 90 degrees, the line lights SL1, SL2 extend in the X direction. Therefore, the scannable width Y of the Y-direction scan is the maximum width max and the scannable width X of the X-direction scan is zero, which cannot be measured. In view of the above, it is necessary to select any appropriate one of the X direction and the Y direction as the scanning direction F according to the rotation angle of the head 25H.

Fig. 11 (a) to (C) are diagrams illustrating a method of determining the scanning direction F. The relationship between the rotation angle of the head 25H and the measurable width of the X-direction scan or the Y-direction scan can be obtained as follows. As shown in fig. 10 (a), the rotation angle of the head 25H is α, the measurable width at α=0 degrees is L, and the distance between the 2 lines SL1, SL2 is D.

As shown in (B) of fig. 11, when the rotation angle=α of the head 25H, the measurable width Lx in the case of performing the X-direction scanning is expressed by the following formula. Where "abs" represents absolute value, ".

Lx＝abs(L·cosα)－abs(D·sinα)

On the other hand, as shown in (C) of fig. 11, when the rotation angle=α of the head 25H, the measurable width Ly in the case where Y-direction scanning is performed is expressed by the following formula.

Ly＝abs(L·sinα)－abs(D·cosα)

The larger the values of the measurable widths Lx, ly described above, the larger the measured width in 1 scan. Therefore, by comparing the value of the X-direction measurable width Lx with the value of the Y-direction measurable width Ly and selecting the larger one as the scanning direction F, it is possible to perform highly efficient height measurement. When the rotation angle=45 degrees, the values of the measurable widths Lx, ly become the same value. In this case, if the scanning distance is short, the time required for scanning can be shortened, and therefore, it is preferable to select one of the X-direction scanning and the Y-direction scanning, which is short.

Fig. 12 is a flowchart showing a scanning direction determination process in element height measurement according to embodiment 2. The scan control unit 32 of the control device 3 rotates the head 25H around the imaging optical axis AX by a rotation angle α (step S1). The rotation angle α is a rotation angle at which the line light SL can be irradiated to the short element C2 surrounded by the tall element C1 as illustrated in fig. 8 (C). Thereafter, a process of how to select one of the X-direction scan and the Y-direction scan is performed.

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). Next, the scan control unit 32 compares the values of the measurable widths Lx, ly. First, it is determined whether an inequality of Lx > Ly is satisfied (step S3). When Lx > Ly is satisfied (yes in step S3), the scan control unit 32 selects X-direction scanning with a wide measurement width (step S4). On the other hand, in the case where Lx > Ly is not satisfied (no in step S3), it is determined whether or not the inequality of Lx < Ly is satisfied (step S5). If Lx < Ly is satisfied (yes in step S5), the scan control unit 32 selects Y-direction scanning (step S6).

On the other hand, if Lx < Ly is not satisfied (no in step S5), lx=ly is set. In this case, the scan control unit 32 compares the scan distance in the case of scanning in the X direction with the scan distance in the case of scanning in the Y direction (step S7). For example, in the example of fig. 8 (B), in the 1 st scan, the area sandwiched by 2 high elements C1 becomes a missing part of the height data. When the defective area is re-measured by the 2 nd scan, it is determined whether or not the scan distance is short when one of the X-direction scan and the Y-direction scan is used. For example, if the defective area is a rectangular area long in the X direction, the scanning distance of the Y-direction scanning to the defective area may be short, thereby contributing to the high speed of the height measurement. Therefore, when the X-direction scanning distance is longer than the Y-direction scanning distance (yes in step S7), the scanning control unit 32 selects the Y-direction scanning (step S8). In contrast, when the Y-direction scanning distance is longer than the X-direction scanning distance (no in step S7), the scanning control unit 32 selects the X-direction scanning (step S9).

[ embodiment 3 ]

In embodiment 3, an example of determining the scanning direction F using the mounting data of the element C is shown. What components C are mounted on the mounting board P in what layout is determined in advance based on the mounting data. The mounting data is information about the shape of the component C and the mounting position on the substrate, and is stored in the mounting data storage section 34. By using the mounting data, the irradiation direction or scanning direction F of the line light SL in which the height data deficiency is not generated or the height data deficiency is minimized can be detected. In embodiment 3, an example is shown in which the measurement processing unit 33 reads out the installation data from the installation data storage unit 34 and determines whether or not a missing portion of the height data has occurred.

Fig. 13 (a) to (E) are schematic diagrams for explaining measurement of the element height according to embodiment 3. Assume that: in the default state shown in fig. 13 (a), the posture and scanning direction F of the head 25H including the camera unit 4 and the line light sources 5A and 5B are determined. The measurement processing section 33 acquires mounting data on the mounting substrate P of the measurement object from the mounting data storage section 34 before performing scanning. The simplest example is a case where a missing part of the height data is not generated even if scanning is performed in a default state. In this case, the 1 st scan is executed only in the default state, and the height measurement is completed. No scan 2 is required.

Fig. 13 (B) and (C) show an example of acquisition of the mounting data. Fig. 13 (B) corresponds to an example of arrangement of the elements C1 and C2 shown in fig. 8 (a), and fig. 13 (C) corresponds to an example of matrix arrangement of the element C shown in fig. 9 (C). If the mounting data is acquired, a three-dimensional model of the mounting substrate P on which the component is mounted can be generated. The measurement processing unit 33 determines a scanning form using the three-dimensional model. Both examples of (B) and (C) of fig. 13 are described above in the case where the missing part of the height data is generated after the scanning is performed in the default state.

In this case, the measurement processing unit 33 performs simulation of the irradiation direction or the scanning direction F of the various types of modified line light SL, and calculates an optimal scanning pattern. Fig. 13 (D) and (E) show examples of determination of the scanning mode in the case where the mounting data of fig. 13 (B) and (C) are acquired, respectively. Fig. 13 (D) corresponds to the scanning pattern of fig. 8 (C), and fig. 13 (E) corresponds to the scanning pattern of fig. 9 (D).

For example, assume that: when the mounting data of fig. 13 (B) is acquired, it is clear that the missing part of the height data does not occur in the scanning mode in which the rotation angle is set for the head 25H as shown in fig. 13 (D). In this case, the 1 st scan is performed in the scan pattern of fig. 13 (D), and the height measurement of the mounting substrate P is ended. In the scanning mode of fig. 13 (D), when the height data deficiency occurs in other portions, for example, the 1 st scanning is performed in the scanning mode of the default state of fig. 13 (a), and the 2 nd scanning is performed in the scanning mode of fig. 13 (D) to supplement the height data. In addition, when the mounting data of fig. 13 (C) is acquired, in the scanning pattern of fig. 13 (E), a height data defect occurs between the element pitches in the Y direction. Therefore, it is decided to perform the 1 st scan in the scan pattern of the default state of fig. 13 (a), and to perform the 2 nd scan in the scan pattern of fig. 13 (E).

[ embodiment 4 ]

In embodiment 4, the following example is shown: when a missing part of the height data is detected in the 1 st scan, it is determined whether or not the missing part occurs due to the scanning direction, and when it is a missing part due to the scanning direction, the 2 nd scan is executed. The height data deficiency is not generated solely due to the shadow SH of the element C. For example, if there are openings or cut-out portions in the mounting substrate P, the reflected light from the substrate surface PS cannot be detected in these portions, and the portions become height data lacking portions. Even if the 2 nd scan is performed on such a missing portion, the height data cannot be obtained, and thus, a working time is generated in vain. Therefore, it is preferable that: even in the case where an area of a height data deficiency is generated, it is determined whether or not the height measurement of the deficiency due to the scanning direction fails, and then the 2 nd scan is performed on the deficient area.

A determination example of whether or not the 2 nd scan is performed on the height data deficiency is shown. Fig. 14 (a) and (B) are schematic diagrams showing one mode of the determination. Here, when the height data missing portion is adjacent to the data-provided area in which the height data is acquired in the scanning direction F, the missing portion is determined as a missing portion from the scanning direction.

Fig. 14 (a) shows a case where the mounting substrate P1 to be measured includes an element layout in which the short elements C2 are arranged between 2 tall elements C1. As shown in (a-1) of fig. 14 (a), it is assumed that: a 1 st scan for height measurement of the mounting substrate P1 is performed with the direction in which the 2 high elements C1 are arranged as the scanning direction. Fig. 14 (a-2) shows an image IM1 of height data obtained based on the 1 st scan. The 2 high elements C1 are shown as data-provided areas where height data higher than the height of the substrate surface PS (mounting surface) is obtained. On the other hand, 2 hatched portions SH1, SH2 whose heights are not detected are shown in the image IM1. An isolated area CA extending in a direction orthogonal to the scanning direction appears in one of the hatched portions SH 1.

One of the shaded portions SH1 is a shaded portion adjacent to the 2 high elements C1 having the data area in the scanning direction. In this case, it can be said that the shadow portion SH1 is blocked by the high element C1 based on the line light SL, and there is a high possibility that measurement failure occurs. In fact, no height data of the short component C2 sandwiched between the tall components C1 is obtained. The isolated area CA is an erroneous area detected as a data-present area due to diffuse reflection of the line light SL or the like. In general, since such a shaped element does not exist, it is regarded as noise data and deleted. On the other hand, the other hatched portion SH2 is not a hatched portion adjacent to any high element C1 in the scanning direction.

Fig. 14 (a-3) shows an example of determination of the execution area of the 2 nd scan in the case where the condition of (a-2) is obtained. The hatched portion SH1 adjacent to the data-on area corresponding to the 2 high elements C1 in the scanning direction is determined as a rescan area RS1 that is the object area of the 2 nd scan. On the other hand, the hatched portion SH2 that is not adjacent to the data-present region in the scanning direction is not regarded as the rescanning region RS1. In the 2 nd scan to be performed later, the height of the rescan area RS1 is measured by changing the irradiation direction of the line light SL or the like. According to this embodiment, the 2 nd scan is not unnecessarily performed, so that the rapidity of the height measurement can be achieved.

Fig. 14 (B) shows a case where the mounting substrate P2 to be measured has a cutout PD2. As shown in (B-1) of fig. 14 (B), the mounting substrate P2 has a cut-out portion PD2 adjacent to the mounted component C on the downstream side in the scanning direction and formed by cutting out a part of the mounting substrate P2. Fig. 14 (B-2) shows an image IM2 of the height data obtained based on the 1 st scan. The mounting region of the component C is shown as a data-bearing region having height data higher than the substrate surface PS. On the other hand, the area of the cut-out PD2 becomes a shadow SH3 without height data.

Fig. 14 (B-3) shows an example of determination of the execution area of the 2 nd scan in the case where the condition of (B-2) is obtained. In this case, although the hatched portion SH3 is adjacent to the data-present region corresponding to the element C, the entire region thereof is not the target region of the 2 nd scan. In the hatched portion SH3, only the region immediately adjacent to the data-bearing region of the element C in the scanning direction, that is, the region located only on the downstream side in the scanning direction, is determined as the rescanning region RS2. The re-scan region RS2 is also a region corresponding to the cut-out portion PD2, and as a result, the height data is not measured even if the 2 nd scan is performed. However, since the execution area of the 2 nd scan is defined, the rapidity of the height measurement is correspondingly facilitated.

Fig. 15 (a) and (B) are schematic diagrams showing other examples of determination as to whether or not to perform the 2 nd scan on the height data deficiency portion. Here, an example is shown in which, when a height data missing portion adjacent to the data-present region in the scanning direction F is a missing portion smaller than a predetermined number of pixels in the image obtained by the 1 st scanning, the missing portion is determined to be due to the scanning direction. In the example of fig. 14, even the cut-out portion PD2 is determined as the object of the 2 nd scan as long as it is adjacent to the data-present region in the scanning direction. In the present determination example, an example of suppressing the defect is shown.

Like fig. 14 (a), fig. 15 (a) shows a case where the mounting substrate P1 to be measured has an element layout in which short elements C2 are arranged between 2 tall elements C1. Assume that: a 1 st scan for height measurement of the mounting substrate P1 is performed with the direction in which the 2 high elements C1 are arranged as the scanning direction. As shown in (a-2) of fig. 15 (a), the area corresponding to the 2 high elements C1 becomes a data-present area, and the shadow portion SH1 and the isolated area CA in which no height is detected are shown therebetween. When determining whether or not the 2 nd scan needs to be performed, the isolated area CA is ignored as noise data, and the width d1 of the shadow SH1, which is a lacking portion of the height data, in the scanning direction is evaluated based on the number of pixels on the image. Here, since the width d1 of the shadow portion SH1 is a missing portion smaller than the predetermined number n of pixels, the shadow portion SH1 is determined as the object of the 2 nd scan.

Like fig. 14 (B), fig. 15 (B) shows a case where the mounting substrate P2 to be measured has the cut-out portion PD2. The mounting substrate P2 has a cutout PD2 adjacent to the element C on the downstream side in the scanning direction. As shown in (B-2) of fig. 15 (B), the region corresponding to the element C becomes a data-present region, and the region of the cutout PD2 becomes a shadow SH3 free of height data. As described above, the width d2 of the shadow portion SH3 in the scanning direction is evaluated based on the number of pixels on the image. Here, since the width d2 of the shadow portion SH3 is a deficiency of a predetermined number of pixels n or more, the shadow portion SH3 is determined not to be the object of the 2 nd scan.

The predetermined number of pixels n can be set to an arbitrary value of 0 or more. For example, when the height data deficiency is detected, if all of them are to be rescanned, n=0 may be set. Alternatively, the pixel number n may be dynamically set based on the relationship between the average height of the periphery of the height data deficiency and the irradiation angle of the line light SL. The number of pixels n may be set with reference to the number of pixels to which the height data is added in the image processing. For example, when set as: if the pixel without height data is 3 pixels or less, the height data without data pixel is derived in the complementary process, and in this case, n=4 is set. In this way, the reference of the height data deficiency portion for determining whether to become the start factor for executing the 2 nd scan can be arbitrarily set based on the pixel number n.

Fig. 16 is a flowchart showing a scanning area determination process in the element height measurement according to embodiment 4. The scan control unit 32 of the control device 3 causes the 1 st scan specified by the default setting to be executed and causes the height measurement of the mounting substrate P to be measured (step S11). Next, the measurement processing unit 33 obtains the height data and the height data deficiency unit from the image obtained in the 1 st scan (step S12).

Next, the measurement processing unit 33 determines whether or not there is an isolated area CA in which the height data is isolated unnaturally as illustrated in fig. 14 (a) in the height data deficiency portion (step S13). When the isolated area CA is detected (yes in step S13), the measurement processing unit 33 performs a process of deleting the isolated area CA because the area is noise data (step S14). If the isolated area CA is not detected (no in step S13), the measurement processing unit 33 determines whether or not there is a data-present area adjacent to the height data deficiency and in which height data higher than the substrate surface PS is detected (step S15).

When the all data area exists (yes in step S15), the measurement processing unit 33 determines whether or not 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 determines whether or not the height data missing portion detected in step S2 is a missing portion adjacent to the data-present region in the scanning direction. If the image is a defective portion adjacent to the scanning direction (yes in step S16), the measurement processing unit 33 determines whether or not the height data defective portion is a defective portion having a width of n or more pixels predetermined in the scanning direction on the image (step S17).

When it is determined that the pixel has a width of not less than the number of pixels n (yes in step S17), the measurement processing unit 33 determines that the height data is a necessary rescanning. In this case, it is determined whether or not all of the specified height measurements are completed (step S18). When the height measurement is not completed (no in step S18), the scan control unit 32 changes the rotation angle of the head 25H and changes the scan direction F as necessary (step S20), and returns to step S11 to execute the 2 nd scan as the rescan. For example, the rescan is performed such that the rotation angle is changed by 15 degrees or the like each time.

When the height measurement is completed (yes in step S18), the measurement processing unit 33 stores the height measurement data on the mounting board P to be measured in the storage area of the control device 3, and updates the data (step S19). On the other hand, when the all data area does not exist in step S15 (no in step S15), when the defective portion adjacent in the scanning direction is not present in step S16 (no in step S16), or when the defective portion having a width equal to or larger than the number of pixels n is determined in step S17 (yes in step S17), the measurement processing unit 33 determines that the process is terminated without re-scanning (step S21).

[ embodiment 5 ]

Embodiment 5 shows an example in which a preferable scanning pattern is detected in advance by using a model substrate. In short, the scan control unit 32 performs a plurality of scans in which the irradiation directions of the line lights SL1 and SL2 are set to different directions with respect to the model substrate, and selects a scan that is suitably used as the 1 st scan from the plurality of scans. In the subsequent height measurement of the mounting board P similar to the model board, the height measurement is performed in the selected scanning mode.

Fig. 17 (a) to (C) are schematic diagrams for explaining measurement of the element height according to embodiment 5. In the present embodiment, a model substrate PM as shown in fig. 17 (a) is prepared. The model board PM is a qualified board obtained by mounting the components C on a board in a predetermined arrangement as in the board design of a certain mounting board product. Here, as in the example in fig. 8 (a), there is a layout in which one short element C2 is surrounded by 4 tall elements C1.

The control device 3 performs a height measurement operation on the model substrate PM before the height measurement of the mounting substrate product is performed. In this height measurement, the scanning control unit 32 performs, for example, a plurality of height measurements in which the head 25H is sequentially rotated and the irradiation directions of the line lights SL1 and SL2 are set to different directions. Fig. 17 (a) shows an example in which the rotation angle of the head 25H is sequentially changed to 0 degrees, 45 degrees, and 90 degrees, and the model substrate PM is scanned in the scanning directions F1, F2, and F3, respectively. In practice, it is preferable to scan the model substrate PM while changing the rotation angle of the head 25H at a small unit angle of about 15 degrees.

The measurement processing unit 33 obtains the height data of the model substrate PM from the images obtained by the respective scans. At this time, the measurement processing unit 33 identifies a missing portion of the height data in each scan, and evaluates how accurately the height measurement is performed based on the installation data. In fig. 17 (a), when the rotation angle of the head 25 h=0 degrees and 90 degrees, the height measurement of the short element C2 cannot be performed, and therefore, the optimum scanning pattern cannot be evaluated. On the other hand, in the case of rotation angle=45 degrees, height measurement including short element C2 can be performed. Therefore, when the mounting board P on which the elements C1 and C2 are mounted in the same arrangement as the model board PM is the object of the height measurement, the measurement processing unit 33 adopts the rotation angle=45 degrees of the head 25H as the scanning mode.

Fig. 17 (B) and (C) show scanning patterns performed on the mounting board P which is the same as the model board PM later. These modes are the same as the scanning modes shown in fig. 8 (C) and (D) of embodiment 1. Fig. 17 (B) shows an example in which the rotation angle=45 degrees of the head 25H is set and scanning is performed while maintaining the scanning direction F1 in which the rotation angle=0 degrees. In fig. 17 (C), an example is shown in which the rotation angle of the head 25 h=45 degrees is set, and the scanning direction F2 corresponding to the rotation angle is set.

According to embodiment 5, a plurality of scans are performed in advance using the model substrate PM, and the optimal scan in which the height data deficiency is most difficult to occur can be detected. Further, by applying the optimum scanning pattern to at least the 1 st scan for the mounting board P similar to the model board PM, it is possible to perform the height measurement without waste.

In embodiment 5, when there is mounting data for calculating the height, volume, and area of the element C, the scanning mode in which the height, volume, and area are closest to the mounting data, which can be obtained from the measurement values in each scan, can be selected. Fig. 18 shows an example of evaluation of the short element C2 and the high element C1 in the scanning direction in terms of the volume ratio, which is the ratio of the volume obtained from the mounting data to the volume obtained by the actual measurement in each scan. The closer the volume ratio is to 100%, the more accurate the measurement is ensured.

Fig. 18 (a) shows the volume ratio of the short element C2 and the tall element C1 in the case where the scanning direction and the rotation angle of the head 25 h=0 degrees. As described above, in the case of 0 degree, the short element C2 becomes a shadow of the tall element C1, and thus accurate height measurement cannot be performed. Therefore, the volume ratio of short element C2 is a low value of 1%. On the other hand, with respect to the high element C1, since there is no obstacle to measurement, a high value of 95% can be obtained in the volume ratio.

Fig. 18 (B) shows the volume ratio in the case where the scanning direction and the rotation angle of the head 25 h=45 degrees. In the case of 45 degrees, the line light SL1, SL2 can also be irradiated to the short element C2. Thus, a high value of 99% can be obtained with respect to the volume ratio of the short element C2. With respect to the high element C1, a high value of 97% can be obtained also in the volume ratio. Fig. 18 (C) shows a volume ratio in the case of a rotation angle=90 degrees. In this case, too, the short element C2 becomes a shadow of the tall element C1, and thus accurate height measurement cannot be performed. Thus, although the volume ratio of the high element C1 can obtain 94%, the volume ratio with respect to the low element C2 is a low value of 2%.

As a result, in the case of the rotation angle=0 degrees and 90 degrees, accurate height measurement cannot be performed at least in the mounting range of the short element C2 and the tall element C1. Thus, a scan with rotation angle=45 degrees is selected. In the actual mounting substrate P, there are a plurality of mounting ranges, and a preferable scanning direction exists for each of these mounting ranges. Preferably, the optimum scanning pattern is set in view of the entire mounting board P by arranging the mounting ranges, the elements, and the like in which the scanning directions are preferably the same.

Fig. 19 is a flowchart showing a scanning direction determination process in the case where mounting data can be used in the element height measurement according to embodiment 5. The scan control unit 32 of the control device 3 performs the scan specified by the default to the model substrate PM, and performs the height measurement of the mounted component C (step S31). Next, the measurement processing unit 33 obtains height data of each element C on the model substrate PM. The measurement processing unit 33 reads the mounting data from the mounting data storage unit 34, and calculates the volume ratio from the volume of the component C1 based on the volume of the height data of the component C actually measured and the volume derived from the actual measurement data (step S32).

Next, it is checked whether or not the measurement of the height of the model substrate PM in the rotation angle and the scanning direction of the head 25H specified in advance is completed (step S33). When all the height measurements are not completed (no in step S33), the scan control unit 32 changes the rotation angle and/or the scan direction of the head 25H (step S35), and causes a new scan to be performed (step S31). On the other hand, when all the height measurements are completed (yes in step S33), the measurement processing unit 33 determines the scanning direction in which the result closest to the mounting data is obtained among all the scans to be tried for each element C, and stores it (step S34).

The above is an example of the scanning direction determination method in the case where the installation data can be used. When the mounting data cannot be used, an optimal scanning direction can be selected based on the relationship between the area of the missing portion of the height data and the scanning direction. Fig. 20 (a) to (C) are diagrams showing the relationship between the shadow parts SH1, SH21, SH22, SH3, which are the height data deficiency parts in the height measurement of the element C, and the scanning direction. Fig. 20 (a), (B), and (C) show measurement results in the case where the scanning direction and the rotation angle of the head 25 h=0 degrees, 45 degrees, and 90 degrees, respectively.

From the images acquired in each of the scans (a) to (C) of fig. 20, the area of the element C, that is, the data-present area is determined. Next, the area of the missing part of the height data adjacent to the data-present area in the scanning direction is obtained. As shown in fig. 20 (a), in the case where the rotation angle=0 degrees, since the long side of the rectangular element C is orthogonal to the scanning direction, a shadow portion SH1 of a relatively large area, that is, the missing portion is shown. On the other hand, in the case of rotation angle=45 degrees in fig. 20 (B), the hatched portions SH21, SH22 of relatively small area are shown at the corners on the downstream side in the scanning direction of the element C1. In the case of rotation angle=90 degrees in fig. 20 (C), a hatched portion SH3 having a larger area than the sum of SH21 and SH22 is shown on the short side of the element C.

Among these scans (a) to (C) of fig. 20, the scan having the smallest area of the lacking portion is selected as the 1 st scan. In the example here, the shadow portions SH21, SH22 detected by the scan set to the rotation angle=45 degrees of (B) of fig. 20 are smallest in area compared with other portions. That is, the rotation angle=45 degrees becomes the scanning of the lacking portion where the height data is most difficult to generate. Therefore, a scan set to a rotation angle=45 degrees of the head 25H is selected at least as the 1 st scan.

Fig. 21 is a flowchart showing a scanning direction determination process in a case where mounting data cannot be used in the component height measurement according to embodiment 5. The scan control unit 32 of the control device 3 performs the scan specified by the default to the model substrate PM, and performs the height measurement of the mounted component C (step S41). Next, the measurement processing unit 33 performs a process of determining a height data deficiency portion with respect to the model substrate PM (step S42). In this step S42, the processing is the same as the processing of steps S12 to S17 of fig. 16 described previously. Here, description is omitted.

Thereafter, the measurement processing unit 33 performs a process of determining the area of the height data deficiency generated in the scan (step S43). Next, it is checked whether or not the measurement of the height of the model substrate PM in the rotation angle and the scanning direction of the head 25H specified in advance is completed (step S44). When all the height measurements are not completed (no in step S44), the scan control unit 32 changes the rotation angle and/or the scan direction of the head 25H (step S46), and causes a new scan to be performed (step S41). On the other hand, when all the height measurements are completed (yes in step S44), the measurement processing unit 33 selects a scan in which the area of the height data deficiency portion is minimized (step S45). The scanning pattern selected here is used for the height measurement of the mounting board P, which is the same as the model board PM, which is performed later.

[ embodiment 6 ]

In embodiment 6, an example of acquiring high-precision height data of a specific element is shown. For example, a highly important element is sometimes required to obtain its shape with high accuracy. In this case, the 1 st scan is performed on the element, and at least the 2 nd scan is performed as if there is a missing portion of the height data in the 1 st scan. That is, whether or not there is a height data deficiency, a plurality of scans are performed on the element. Then, the height data of the element is obtained by synthesizing the height data obtained from at least the images obtained by the 1 st scan and the 2 nd scan.

Fig. 22 (a) to (D) are schematic diagrams for explaining measurement of the element height according to embodiment 6. The measurement object is a specific element CP mounted on the mounting substrate P. The specific element CP is an important element such as a large scale integrated circuit element. As shown in fig. 22 (a), the specific element CP is scanned a plurality of times by making the rotation angle of the head 25H different, that is, the irradiation directions of the line lights SL1, SL2 are scanned a plurality of times by making the specific element CP different. In fig. 22 (a), an example is shown in which the 1 st scan with the X direction as the scanning direction F1 and the 2 nd scan with the Y direction as the scanning direction F2 are performed for the specific element CP.

Fig. 22 (B) shows the height data of the specific element CP obtained from the image acquired in the 1 st scan, and the shadow portion SHx which is the height data deficiency. Although the hatched portion SHx is shown at the X-side XS of the specific element CP, there is no hatched portion at the Y-side YS. Fig. 22 (C) shows the height data of the specific element CP based on the 2 nd scan and the hatched portion SHy. Although the shadow portion SHy is shown on the Y side YS of the particular element CP, there is no shadow portion on the X side XS. In the height measurement based on scan 1, the height data of the X-side XS is not determined. Further, in the height measurement based on the 2 nd scan, the height data of the Y side YS is not determined. However, as shown in fig. 22 (D), if the height data obtained in the 1 st scan and the 2 nd scan are combined, the uncertainty due to the shadow portions SHx, SHy can be eliminated. Therefore, the height data of the specific element CP can be obtained with high accuracy.

Fig. 23 is a flowchart showing a high-precision element height data generation process according to embodiment 6. The scan control unit 32 of the control device 3 causes the specific element CP to perform the scan specified by the default setting, and causes the height of the specific element CP to be measured (step S51). Based on the height measurement, the measurement processing unit 33 obtains the height data and the shaded portions SHx, SHy of the specific element CP (step S52).

Next, it is checked whether or not the height measurement required for data synthesis as exemplified in fig. 22 (B) to (D) is completed (step S53). When all the height measurements are not completed (no in step S53), the scan control unit 32 changes the rotation angle and/or the scan direction of the head 25H (step S54), and causes a new scan to be executed (step S51). On the other hand, when the height measurement is completed (yes in step S53), the measurement processing unit 33 performs the height data synthesis processing (step S55).

In step S55, as illustrated in fig. 22 (C) and (D), when only one of the X side XS and the Y side YS of the specific element CP has the shadow portions SHx and SHy, the synthesis processing of the height data directly using the other side is performed. That is, the height data of the specific element CP is directly generated using the height data of the Y-side YS obtained in the 1 st scan and the height data of the X-side XS obtained in the 2 nd scan. In contrast, in a plurality of scans, both the X-side XS and the Y-side YS may show hatched portions SHx and SHy. In this case, the height data can be generated by employing the average, middle, maximum, or minimum value of the height data obtained by the plurality of scans.

Other modified embodiment

While various embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modified embodiments such as the following can be adopted.

(1) In the above embodiment, an example in which the camera unit 4 and the line light sources 5A, 5B are integrally rotated by rotating the head 25H around the imaging optical axis AX is shown. 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 integrally so as to maintain the relationship between the posture of the imaging range 4A of the camera unit 4 and the irradiation directions of the line light SL1 and SL 2. In contrast, in the modification shown in fig. 24 (B), an example is shown in which only the light sources 5A and 5B are rotated without rotating the camera unit 4. In this case, the relationship between the posture of the imaging range 4A and the irradiation directions of the line lights SL1, SL2 changes from the case of fig. 24 (a). The scanning direction can be set to be orthogonal to the extending direction of the line light SL1 and SL 2.

(2) In general, the entire number of pixels of the image data captured by the camera unit 4 is transmitted to the control device 3 side. Alternatively, only a part of the image data may be transferred in order to achieve a higher processing speed. Fig. 25 is a schematic diagram showing an example of limiting the image data used. In the optical cutting method, peripheral regions of the line lights SL1 and SL2 are necessary for the image data. For example, assume a case where the irradiation of the light rays SL1, SL2 is performed as in fig. 24 (B). In this case, the image data of the entire imaging range 4A provided in the CMOS sensor or the like of the camera body 41 is not transferred, but as shown in fig. 25, only the data of the image existing in the imaging region ROI of the line lights SL1, SL2 is cut and transferred. This can achieve a high speed of data processing.

[ invention included in the above embodiment ]

A workpiece height measuring apparatus according to an aspect of the present invention includes: a photographing section having an imaging optical axis in a plumb direction and photographing an image of a workpiece; a line light projection unit having a projection optical axis with a predetermined intersection angle with respect to the imaging optical axis, the line light projection unit being capable of irradiating a workpiece with line light from a plurality of directions; a scanning drive unit that moves the imaging unit and the line light projection unit and scans a workpiece; and a measuring unit that controls the scanning driving unit to perform the scanning, and obtains height data of the workpiece by a light-cutting method based on an image obtained by the scanning; the measurement unit irradiates the line light to a workpiece from a predetermined irradiation direction to cause the 1 st scan to be executed, the measurement unit determines whether or not a missing part of the height data of the workpiece exists in the height data obtained from the image obtained by the 1 st scan, and the measurement unit causes the irradiation direction of the line light to be executed in a 2 nd scan having a different azimuth from the 1 st scan when the missing part is detected.

According to this work height measuring apparatus, in the case where a missing portion is detected in the height data obtained by the 1 st scan, the 2 nd scan is performed in which the irradiation direction of the line light is set to an orientation different from that of the 1 st scan. If there are a plurality of workpieces having different sizes or if the workpieces are dense, there is a possibility that the workpieces are not irradiated with the line light due to shadows or the like entering other workpieces in the 1 st scan. Alternatively, in the case of a workpiece having surface irregularities, in the 1 st scan, a shadow portion which is not irradiated with line light may be generated due to shielding by a convex portion or the like. However, by performing the 2 nd scan, height measurements can be made again for these shadow areas. Therefore, the height of the workpiece can be accurately measured.

In the workpiece height measuring apparatus described above, the measuring unit sets a scanning direction to a predetermined 1 st scanning direction in a state where a posture of an imaging range of the imaging unit and an irradiation direction of the line light are set to predetermined conditions, and causes the 1 st scanning to be performed, and causes the measuring unit to maintain the scanning direction in the 1 st scanning direction, and causes the imaging optical axis of the imaging Fan Weirao to rotate, and causes the orientation of the irradiation direction of the line light to be changed so that a relationship between the irradiation direction of the line light and the posture of the imaging range is maintained to be the same as the 1 st scanning, and causes the 2 nd scanning to be performed.

According to the work height measuring apparatus, the 1 st scan and the 2 nd scan are performed without changing the scanning direction. Even if the scanning direction is not changed, the direction of the imaging range and the irradiation direction of the line light are different in the 1 st scan and the 2 nd scan. Therefore, by the 2 nd scan, the height of the region where the missing portion of the height data of the workpiece is generated can be measured. In the 1 st and 2 nd scans, the relationship between the posture of the imaging range and the irradiation direction of the line light is maintained to be the same, so that the height data can be efficiently derived.

In the workpiece height measuring apparatus described above, the measuring unit sets a scanning direction to a predetermined 1 st scanning direction in a state where a posture of an imaging range of the imaging unit and an irradiation direction of the line light are set to predetermined conditions, the measuring unit sets a scanning direction to a 2 nd scanning direction different from the 1 st scanning direction, rotates the imaging optical axis of the imaging Fan Weirao according to the 2 nd scanning direction, and changes an orientation of the irradiation direction of the line light so that a relationship between the irradiation direction of the line light and the posture of the imaging range is maintained to be the same as the 1 st scanning, and causes the 2 nd scanning to be performed.

According to this workpiece height measuring device, the height of the region where the missing portion of the height data of the workpiece is generated can be measured by the 2 nd scan by simply changing the scanning direction.

In the workpiece height measuring apparatus, it is preferable that the scanning drive unit includes a 1 st movement mechanism that horizontally moves the imaging unit and the line light projection unit in a 1 st movement direction and a 2 nd movement mechanism that horizontally moves the imaging unit and the line light projection unit in a 2 nd movement direction orthogonal to the 1 st movement direction in a horizontal plane, and the measuring unit selects one of the 1 st movement mechanism and the 2 nd movement mechanism to operate when the 1 st scanning and the 2 nd scanning are performed.

According to the workpiece height measuring apparatus, the scanning driving section drives only one of the 1 st moving mechanism and the 2 nd moving mechanism at the time of the scanning operation. Therefore, the driving control of the scanning driving section can be simplified.

In this case, it is preferable that the measuring unit selects one of the 1 st moving mechanism and the 2 nd moving mechanism having a shorter scanning distance when selecting the mechanism. According to this aspect, the total scanning distance required for workpiece scanning can be shortened, and the high-speed measurement can be facilitated.

In the workpiece height measuring apparatus, it is preferable that the workpiece is a substrate on which a plurality of elements are mounted, the measuring unit acquires element mounting data including information on a shape of the element and a mounting position on the substrate, and determines whether or not a missing portion of the height data is present based on the element mounting data.

According to the workpiece height measuring device, the relation between the irradiation direction or scanning direction of the line light and the occurrence position of the missing part of the height data can be grasped in advance based on the element mounting data. Therefore, the irradiation direction or scanning direction of the line light with the small number of the lacking portions can be set in advance.

In the workpiece height measuring apparatus, it is preferable that the measuring unit determines whether or not a cause of the missing portion is a scan direction when the missing portion of the height data is detected, and causes the 2 nd scan to be executed when the missing portion is a scan direction.

For example, if there is an opening or a cut-out in the setting base of the workpiece, a missing part of the height data may occur. According to the workpiece height measuring apparatus described above, the 2 nd scan is executed only when a missing portion of the height data is generated due to the scanning direction. Therefore, the 2 nd scan is not unnecessarily performed.

In the workpiece height measuring apparatus, the workpiece may be mounted on a mounting surface of a substrate, the measuring unit may determine a data-included area in which height data higher than a height of the mounting surface is obtained, and the measuring unit may cause the 2 nd scan to be executed when the missing portion is adjacent to the data-included area in a scanning direction.

In the case where the missing portion of the height data and the data-present area are adjacent in the scanning direction, the missing portion occurs because of a high possibility of a shadow at the time of line light irradiation. According to the workpiece height measuring apparatus described above, in this case, it is determined that the data missing portion is a missing portion due to the scanning direction. Therefore, it can be appropriately determined whether the 2 nd scan is necessary.

In the workpiece height measuring apparatus, the measuring unit may cause the 2 nd scan to be executed when the missing portion adjacent to the data-present region in the scanning direction is a missing portion smaller than a predetermined number of pixels in the image obtained by the 1 st scan.

According to this workpiece height measuring device, a reference for determining whether the missing portion becomes a start factor for executing the 2 nd scan can be arbitrarily set based on the number of pixels.

In the workpiece height measuring apparatus, the workpiece may be a workpiece mounted on a mounting surface of a substrate, the measuring unit may be configured to determine the height data by performing a plurality of scans in which the irradiation direction of the line light is set to a different direction, with respect to a model substrate in which the workpiece is mounted on the substrate in a predetermined arrangement, and the scanning driving unit may be configured to select a scan used at least as the 1 st scan from the plurality of scans when the workpiece mounted on the substrate in the same arrangement as the model substrate is a target of the height measurement.

According to this work height measuring apparatus, since a plurality of scans are performed using the model substrate, it is possible to detect the optimum scan in which the height data deficiency is most difficult to occur. Further, the optimum scan detected in advance can be applied to the same mounting substrate as the model substrate.

In this case, it is preferable that the measuring unit determines a data-on-area in which height data higher than the height of the mounting surface is obtained in the plurality of scans, the measuring unit obtains an area of a missing portion of the height data adjacent to the data-on-area in the scanning direction, and the measuring unit selects a scan in which the area of the missing portion is smallest from the plurality of scans as the 1 st scan.

According to this work height measuring apparatus, the 1 st scan can be performed in a scan mode in which the area of occurrence of the missing portion of the height data is minimized.

In the above-described workpiece height measuring apparatus, it is preferable that the measuring unit is configured to perform the 1 st scan on one workpiece, and to perform the 2 nd scan as if there is the defect, and the measuring unit is configured to synthesize height data obtained from images obtained in the 1 st scan and the 2 nd scan to obtain the height data of the one workpiece.

According to this work height measuring apparatus, the height data of the work can be obtained with high accuracy by combining the height data obtained by the 2 scans, respectively.

In the workpiece height measuring apparatus, it is preferable that the scanning drive unit includes a 1 st movement mechanism for horizontally moving the imaging unit and the line light projection unit in a 1 st movement direction and a 2 nd movement mechanism for horizontally moving the imaging unit and the line light projection unit in a 2 nd movement direction orthogonal to the 1 st movement direction in a horizontal plane, the 1 st movement mechanism includes a 1 st encoder for detecting a position of the 1 st movement direction at a predetermined resolution, the 2 nd movement mechanism includes a 2 nd encoder for detecting a position of the 2 nd movement direction at the predetermined resolution, and the imaging unit captures an image of the workpiece in synchronization with position detection signals output from the 1 st encoder and the 2 nd encoder at the time of scanning.

According to this work height measuring device, since imaging is performed in synchronization with the position detection signals output from the 1 st and 2 nd encoders, the height data of the work can be acquired at the same pitch regardless of the scanning direction.

In the above-described workpiece height measuring apparatus, it is preferable that the apparatus further includes: a slider movable in a scanning direction; a head portion supported by the slider and rotatably holding the imaging portion and the line light projecting portion about the imaging optical axis; and a rotation mechanism that rotates the imaging unit and the line light projection unit integrally or rotates both of them.

According to this work height measuring device, the imaging unit and the line light projecting unit can be rotated integrally or individually. Therefore, the rotation angle of the imaging region and the irradiation direction of the line light can be freely set.

In the workpiece height measuring apparatus, the plurality of line light projection units may be arranged at predetermined intervals on a circumference centered on the imaging optical axis of one of the imaging units.

According to this work height measuring device, the irradiation direction of the line light can be changed by selecting at least one of the plurality of line light projection sections arranged along the circumference.

Another aspect of the present invention relates to a mounting board inspection apparatus including: a measuring table for carrying in the mounting substrate with the components mounted thereon; and the workpiece height measuring device performs height measurement using the element of the mounting substrate carried into the measuring table as the workpiece.

According to this mounting board inspection apparatus, the component height can be accurately measured regardless of the arrangement state of the components, and thus, appropriate mounting board inspection can be performed.

Claims (16)

1. A workpiece height measurement apparatus characterized by comprising:

a photographing section having an imaging optical axis in a plumb direction and photographing an image of a workpiece;

a line light projection unit having a projection optical axis with a predetermined intersection angle with respect to the imaging optical axis, the line light projection unit being capable of irradiating a workpiece with line light from a plurality of directions;

a scanning drive unit that moves the imaging unit and the line light projection unit and scans a workpiece; the method comprises the steps of,

a measuring unit that controls the scanning driving unit to perform the scanning and obtains height data of the workpiece by a light-cutting method based on an image obtained by the scanning; wherein,

the measuring section irradiates the line light to the workpiece from a predetermined irradiation direction to cause the 1 st scan to be executed,

The measuring unit determines whether or not a missing part of the height data of the workpiece exists in the height data obtained from the image obtained by the 1 st scan,

when the measurement unit detects the defect, the measurement unit sets the irradiation direction of the line light to be a 2 nd scan having a different azimuth from the 1 st scan.

2. The workpiece height measuring device as set forth in claim 1, wherein,

the measuring unit sets a scanning direction to a predetermined 1 st scanning direction in a state where a posture of an imaging range of the imaging unit and an irradiation direction of the line light are set to predetermined conditions, so that the 1 st scanning is performed,

the measuring unit rotates the imaging optical axis of the imaging Fan Weirao while maintaining the scanning direction in the 1 st scanning 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 range is maintained to be the same as in the 1 st scanning, thereby executing the 2 nd scanning.

3. The workpiece height measuring device as set forth in claim 1, wherein,

the measuring unit sets a scanning direction to a predetermined 1 st scanning direction in a state where a posture of an imaging range of the imaging unit and an irradiation direction of the line light are set to predetermined conditions, so that the 1 st scanning is performed,

The measuring unit sets a scanning direction to a 2 nd scanning direction different from the 1 st scanning direction, rotates the imaging optical axis of the imaging Fan Weirao according to the 2 nd scanning 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 range is maintained to be the same as the 1 st scanning, thereby executing the 2 nd scanning.

4. The workpiece height measuring device as set forth in claim 1, wherein,

the scanning driving part comprises a 1 st moving mechanism for horizontally moving the shooting part and the line light projecting part in a 1 st moving direction and a 2 nd moving mechanism for horizontally moving the shooting part and the line light projecting part in a 2 nd moving direction orthogonal to the 1 st moving direction on a horizontal plane,

when the 1 st scan and the 2 nd scan are executed, the measurement unit selects one of the 1 st moving mechanism and the 2 nd moving mechanism to operate.

5. The workpiece height measuring device as set forth in claim 4, wherein,

the measuring unit selects one of the 1 st moving mechanism and the 2 nd moving mechanism having a shorter scanning distance.

6. The workpiece height measurement device as recited in any one of claims 1 to 5, wherein,

the workpiece is a substrate on which a plurality of elements are mounted,

the measuring unit acquires component mounting data including information on the shape of the component and the mounting position on the substrate, and determines whether or not there is a missing portion of the height data based on the component mounting data.

7. The workpiece height measurement device as recited in any one of claims 1 to 5, wherein,

the measurement unit determines whether or not the cause of the missing portion is due to the scanning direction when the missing portion of the height data is detected, and causes the 2 nd scan to be executed when the missing portion is due to the scanning direction.

8. The workpiece height measurement device as set forth in claim 7 wherein,

the workpiece is a workpiece mounted on a mounting surface of a substrate,

the measuring unit determines a data-containing area in which height data higher than the height of the mounting surface is obtained,

the measurement unit causes the 2 nd scan to be executed when the missing portion is adjacent to the all-data area in a scanning direction.

9. The workpiece height measuring device as set forth in claim 8, wherein,

The measurement unit causes the 2 nd scan to be executed when the missing portion adjacent to the data-present region in the scan direction is a missing portion smaller than a predetermined number of pixels in the image obtained by the 1 st scan.

10. The workpiece height measurement device as recited in any one of claims 1 to 5, wherein,

the workpiece is a workpiece mounted on a mounting surface of a substrate,

the measuring section is configured to execute a plurality of scans in which the irradiation direction of the line light is set to different directions, with respect to a model substrate in which the work is mounted on the substrate in a predetermined arrangement,

the measuring unit obtains height data by selecting a scan to be used at least as the 1 st scan from among the plurality of scans when a workpiece mounted on a substrate in the same arrangement as the model substrate is a target of height measurement.

11. The workpiece height measurement device as set forth in claim 10 wherein,

the measuring unit determines a data-containing area in which height data higher than the height of the mounting surface is obtained in the plurality of scans,

the measuring unit obtains an area of a missing part of the height data adjacent to the all-data area in the scanning direction,

The measurement unit selects, as the 1 st scan, a scan in which the area of the missing portion is smallest from among the plurality of scans.

12. The workpiece height measurement device as recited in any one of claims 1 to 5, wherein,

the measuring section causes the 1 st scan to be performed for one workpiece, and causes the 2 nd scan to be performed as if there is the missing section,

the measuring unit synthesizes the height data obtained from the images obtained in the 1 st scan and the 2 nd scan to obtain the height data of the one workpiece.

13. The workpiece height measuring device as set forth in claim 1, wherein,

the scanning driving part comprises a 1 st moving mechanism for horizontally moving the shooting part and the line light projecting part in a 1 st moving direction and a 2 nd moving mechanism for horizontally moving the shooting part and the line light projecting part in a 2 nd moving direction orthogonal to the 1 st moving direction on a horizontal plane,

the 1 st moving mechanism includes a 1 st encoder that detects a position of the 1 st moving direction at a prescribed resolution, the 2 nd moving mechanism includes a 2 nd encoder that detects a position of the 2 nd moving direction at the prescribed resolution,

The image capturing unit captures an image of a workpiece in synchronization with a position detection signal output from the 1 st encoder and the 2 nd encoder during scanning.

14. The workpiece height measurement device as set forth in any one of claims 1 to 13, further comprising:

a slider movable in a scanning direction;

a head portion supported by the slider and rotatably holding the imaging portion and the line light projecting portion about the imaging optical axis; the method comprises the steps of,

and a rotation mechanism that rotates the imaging unit and the line light projection unit integrally or rotates both of them.

15. The workpiece height measurement device as recited in any one of claims 1 to 13, wherein,

the plurality of 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.

16. A mounting substrate inspection apparatus, characterized by comprising:

a measuring table for carrying in the mounting substrate with the components mounted thereon; the method comprises the steps of,

the workpiece height measurement device according to any one of claims 1 to 15, wherein a component of the mounting substrate carried into the measurement table is used as the workpiece for height measurement.