Inspection device and position correction method for inspection device

Abstract

To correct positional displacement of a visual field in an in-plane direction caused by the movement in a height direction of an imaging device.SOLUTION: An inspection device includes: an imaging device for imaging an object in an imaging direction along a height direction with respect to a prescribed surface, a moving device for moving the imaging device in the respective directions of an in-plane direction along the prescribed surface and the height direction; and an image processing unit for processing an image captured by the imaging device. The image processing unit acquires a plurality of tool images obtained by capturing a tool by the imaging devices arranged in a plurality of positions in the height direction, acquires the position coordinates of a plurality of reference points in which relative positions in the in-plane direction are known mutually and positions in the height direction are different from the plurality of tool images, and calculates a position correction amount in the in-plane direction corresponding to the position in the height direction of the imaging device on the basis of the position coordinates of the plurality of reference points.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an inspection apparatus and a method for correcting the position of the inspection apparatus.

Background Art

[0002] In the technical field related to inspection apparatuses, an inspection apparatus as disclosed in Patent Document 1 is known. The inspection apparatus includes a substrate camera that captures an inspection image of a substrate on which a plurality of components are mounted, and a moving mechanism that moves the substrate camera in the Y direction (horizontal direction) and the Z direction (vertical direction).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, an inspection image is captured by arranging the substrate camera at a height position corresponding to the height of each component. Due to errors related to the assembly of the substrate camera with respect to the moving mechanism and errors related to the guiding accuracy of the moving mechanism in the height direction, when the substrate camera is moved in the height direction, a positional deviation of the field of view of the substrate camera in the in-plane direction along the substrate occurs. In order to improve the inspection accuracy, it is desirable to correct the positional deviation of the field of view in the in-plane direction accompanying the movement of the imaging device in the height direction.

[0005] An object of the present disclosure is to correct the positional deviation of the field of view in the in-plane direction accompanying the movement of the imaging device in the height direction.

Means for Solving the Problems

[0006] This specification discloses an inspection apparatus. The inspection apparatus includes an imaging device that images an object in an imaging direction along a height direction with respect to a predetermined plane, a moving device that moves the imaging device in the height direction, and an image processing unit that processes an image captured by the imaging device. The image processing unit acquires a plurality of jig images obtained by imaging a jig with the imaging device arranged at a plurality of positions in the height direction, acquires position coordinates of a plurality of reference points whose relative positions in the in-plane direction along the predetermined plane are known and whose positions in the height direction are different from the plurality of jig images, and calculates an in-plane position correction amount corresponding to the position of the imaging device in the height direction based on the position coordinates of the plurality of reference points.

[0007] This specification discloses a position correction method for an inspection apparatus. The position correction method for an inspection apparatus includes steps of acquiring a plurality of jig images by arranging an imaging device that images an object in an imaging direction along a height direction with respect to a predetermined plane at a plurality of positions in the height direction by a moving mechanism and imaging a jig, acquiring position coordinates of a plurality of reference points whose relative positions in the in-plane direction along the predetermined plane are known and whose positions in the height direction are different from the plurality of jig images, and calculating an in-plane position correction amount corresponding to the position of the imaging device in the height direction based on the position coordinates of the plurality of reference points.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to correct the in-plane position shift of the visual field accompanying the movement of the imaging device in the height direction.

Brief Description of the Drawings

[0009]

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MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. Also, some components may not be used.

[0011] In the embodiment, an XYZ orthogonal coordinate system is defined, and the positional relationships of each part will be described with reference to the XYZ orthogonal coordinate system. The direction parallel to the X-axis within a predetermined plane is defined as the X-axis direction. The direction parallel to the Y-axis within the predetermined plane orthogonal to the X-axis is defined as the Y-axis direction. The direction parallel to the Z-axis orthogonal to the predetermined plane is defined as the Z-axis direction. The rotation or inclination direction centered on the X-axis is defined as the θX direction. The rotation or inclination direction centered on the Y-axis is defined as the θY direction. The rotation or inclination direction centered on the Z-axis is defined as the θZ direction. The predetermined plane including the X-axis and the Y-axis is appropriately referred to as the XY plane. The predetermined plane is parallel to the horizontal plane. The Z-axis is parallel to the vertical line. The Z-axis is orthogonal to the predetermined plane. The Z-axis direction is the vertical direction (height direction with respect to the predetermined plane). The +Z direction is the upward direction, and the -Z direction is the downward direction.

[0012] [Inspection device] FIG. 1 is a diagram schematically showing an inspection device 1 according to an embodiment. In the embodiment, the inspection device 1 is an automated optical inspection device (AOI), which is a type of appearance inspection device.

[0013] The inspection device 1 includes a table 3 that supports the object 2, a table driving device 4 that tilts the table 3, an illumination device 5 that illuminates the object 2 supported on the table 3 with illumination light, an imaging device 8 having an optical system 6 and an image sensor 7, a moving device 9 that moves the imaging device 8, a control device 10 including a computer system, and a display device 11 that displays display data.

[0014] The object 2 is the inspection object of the inspection device 1. The object 2 is, for example, a mounting substrate on which a plurality of electronic components are mounted. In this case, the object 2 includes a substrate CB and a plurality of components P mounted on the substrate CB. The inspection device 1 performs an appearance inspection of a mounting substrate on which a plurality of components P are mounted on the substrate CB.

[0015] Table 3 has a support surface 13 that supports at least a part of the object 2. The support surface 13 of the table 3 faces the +Z direction. The support surface 13 is parallel to the XY plane. The object 2 is supported by the table 3 such that the mounting surface on which the component P is mounted faces upward. With the object 2 supported by the table 3, each component P protrudes upward from the mounting surface of the substrate CB.

[0016] The table driving device 4 can tilt the table 3 in each of the θX direction and the θY direction. When the table 3 tilts, the object 2 supported by the table 3 tilts in each of the θX direction and the θY direction. The table driving device 4 has a plurality of actuators 14 that generate the power to tilt the table 3, and a base member 15 that supports the table 3 via the plurality of actuators 14. The table driving device 4 adjusts the tilt of the table 3 so that the surface to be inspected of the object 2 (the mounting surface of the substrate CB) is parallel to the XY plane.

[0017] The lighting device 5 illuminates the object 2 supported by the table 3 with illumination light. The lighting device 5 is disposed above the table 3. The lighting device 5 has an inclined lighting device 16 and a coaxial lighting device 17.

[0018] The inclined lighting device 16 has a plurality of annular light sources 18 and a support member 19 that supports the plurality of light sources 18. As the light source 18, a light emitting diode (LED: Light Emitting Diode) is exemplified. The light source 18 emits white light as illumination light.

[0019] In an embodiment, the light source 18 includes a first light source 18A having a first inner diameter, a second light source 18B having a second inner diameter larger than the first inner diameter, and a third light source 18C having a third inner diameter larger than the second inner diameter. Among the plurality of light sources 18, the first light source 18A is arranged at the position farthest from the table 3, the second light source 18B is arranged at a position farther from the table 3 next to the first light source 18A, and the third light source 18C is arranged at the position closest to the table 3. That is, among the plurality of light sources 18, the first light source 18A is arranged at the highest position, the second light source 18B is arranged at a high position next to the first light source 18A, and the third light source 18C is arranged at the lowest position. When the object 2 is not supported on the table 3, the illumination light emitted from the first light source 18A enters the support surface 13 at a first incident angle. The illumination light emitted from the second light source 18B enters the support surface 13 at a second incident angle. The illumination light emitted from the third light source 18C enters the support surface 13 at a third incident angle. The first incident angle, the second incident angle, and the third incident angle are different.

[0020] The coaxial illumination device 17 includes a light source 21 arranged around the incident surface 20 of the optical system 6 of the imaging device 8, and a support member 22 that supports the light source 21. A plurality of light sources 21 are arranged at intervals around the incident surface 20 of the optical system 6. As the light source 21, a light emitting diode (LED) is exemplified. The light source 21 emits white light as illumination light.

[0021] The light source 21 emits illumination light in a direction parallel to the optical axis AX of the optical system 6. In the embodiment, the optical axis AX of the optical system 6 is parallel to the Z axis.

[0022] The imaging device 8 images the object 2 illuminated by the illumination device 5. The imaging device 8 is arranged above the table 3. The imaging device 8 images the object 2 in an imaging direction along the height direction (Z-axis direction) with respect to a predetermined plane (XY plane). The imaging direction of the imaging device 8 is the -Z direction. The imaging device 8 images the object 2 supported on the table 3 from above.

[0023] The imaging device 8 includes an optical system 6 and an image sensor 7. The optical axis AX of the optical system 6 is disposed inside the annular light source 18. The imaging direction of the imaging device 8 coincides with the direction in which the optical axis AX extends. The image sensor 7 acquires an image of the object 2 via the optical system 6. As the image sensor 7, a CCD (Couple Charged Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is exemplified. The image captured by the imaging device 8 is a color image. Note that the image captured by the imaging device 8 may also be a monochrome image.

[0024] In the embodiment, the imaging device 8 is a fixed-focus type imaging device. The optical system 6 is a fixed-focus optical system with a fixed focal length. The focal point of the optical system 6 exists below the front end surface (lower end surface) of the optical system 6. The relative position between the optical system 6 and the focal point does not change.

[0025] The moving device 9 moves the imaging device 8 at least in the height direction. In the first embodiment, the moving device 9 moves the imaging device 8 in each direction in the in-plane direction (along a predetermined plane (XY plane)) and the height direction. The in-plane direction includes the X-axis direction and the Y-axis direction. The height direction is the Z-axis direction. The moving device 9 includes a Z drive unit 23 that holds the body of the imaging device 8 and moves it in the Z-axis direction, and an XY drive unit 24 that moves the Z drive unit 23 in the X-axis direction and the Y-axis direction. When the imaging device 8 moves in each of the XYZ directions, the lighting device 5 also moves in each of the XYZ axial directions together with the imaging device 8.

[0026] The Z drive unit 23 includes a Z actuator that generates a driving force for moving the imaging device 8 in the Z-axis direction. The Z drive unit 23 includes a transmission mechanism that moves the imaging device 8 in the Z-axis direction by the driving force of the Z actuator, and a guide member that guides the movement of the imaging device 8 in the Z-axis direction. The Z actuator is, for example, an electric motor. The transmission mechanism is, for example, a screw feed mechanism including a ball screw shaft and a ball nut. The guide member is, for example, a linear guide including a linear rail and a slide.

[0027] The XY drive unit 24 supports the imaging device 8 via the Z drive unit 23. The XY drive unit 24 moves the imaging device 8 in the in-plane direction (X-axis direction and Y-axis direction) by moving the Z drive unit 23 in the X-axis direction and the Y-axis direction. The XY drive unit 24 includes an X actuator that generates a driving force for moving the imaging device 8 in the X-axis direction, and a Y actuator that generates a driving force for moving the imaging device 8 in the Y-axis direction. The XY drive unit 24 is configured by a so-called orthogonal robot (XY robot).

[0028] When the imaging device 8 moves within the XY plane, the visual field range 25 of the imaging device 8 moves in the X-axis direction and the Y-axis direction with respect to the object 2. The visual field range 25 of the imaging device 8 is the range that can be imaged by the imaging device 8. The visual field range 25 of the imaging device 8 is smaller than the planar size of the object 2. By adjusting the relative position between the visual field range 25 of the imaging device 8 and the object 2 within the XY plane, the imaging device 8 can individually image a plurality of ranges of the object 2. The inspection device 1 can synthesize images of a plurality of ranges of the object 2 by image processing.

[0029] The height dimensions of the plurality of components P mounted on the substrate CB of the object 2 vary depending on the component type. In FIG. 1, the plurality of components P include a component Pa with a small height, a component Pb with a medium height, and a component Pc with a large height. The imaging device 8 is moved in the Z-axis direction according to the height position of the inspection site. When the inspection site is part or all of the component P, the imaging device 8 is moved in the Z-axis direction according to the height dimension of the component P. When imaging, the height position of the imaging device 8 is adjusted by the Z drive unit 23 so that the inspection site of the component P existing within the visual field range 25 is arranged within the depth of field range including the focus of the optical system 6 (that is, so that the inspection site is in focus).

[0030] The control device 10 controls the table drive device 4, the lighting device 5, the imaging device 8, and the moving device 9. The control device 10 includes an arithmetic processing unit including a processor such as a CPU (Central Processing Unit), and a storage device including a memory and a storage such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The arithmetic processing unit performs arithmetic processing according to a computer program stored in the storage device. Note that the control device 10 may be configured by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0031] The display device 11 has a display screen for displaying display data. Examples of the display device 11 include flat panel displays such as a liquid crystal display (LCD: Liquid Crystal Display) or an organic EL display (OELD: Organic Electroluminescence Display). The display data displayed on the display device 11 includes an image of the object 2. An operator can check the state of the object 2 on the display screen of the display device 11.

[0032] [Control Device] FIG. 2 is a functional block diagram showing the control device 10 according to the embodiment. The control device 10 includes a lighting control unit 26, an imaging position control unit 27, an imaging control unit 28, an image acquisition unit 29, an image processing unit 30, a table control unit 31, a display control unit 32, and a storage unit 33.

[0033] The lighting control unit 26 outputs a control command to the lighting device 5 to illuminate the object 2 supported on the table 3 with illumination light.

[0034] The imaging position control unit 27 issues a control command to the moving device 9 to move the imaging device 8 in the X, Y, and Z axis directions. The imaging position control unit 27 outputs a control command to the moving device 9 to adjust the relative position in the height direction (Z-axis direction) between the visual field range 25 of the imaging device 8 and the inspection part of the object 2. The imaging position control unit 27 acquires the position coordinates of each axis direction of the moving device 9 based on the detection signals from position information acquisition means such as encoders or position sensors respectively provided in the Z drive unit 23 and the XY drive unit 24. The imaging position control unit 27 moves the imaging device 8 based on the acquired position coordinates of each axis direction.

[0035] The imaging control unit 28 outputs a control command to the imaging device 8 to capture an image of the object 2 arranged in the visual field range 25 of the optical system 6. The imaging control unit 28 outputs a control command to the imaging device 8 to control imaging conditions including at least one of the timing of capturing the object 2, the shutter speed, and the aperture of the optical system 6.

[0036] The image acquisition unit 29 acquires an image of the object 2 arranged in the visual field range 25 of the optical system 6 from the imaging device 8.

[0037] The image processing unit 30 processes the image captured by the imaging device 8. The image processing unit 30 acquires the image from the image acquisition unit 29 and performs image processing on the image. The image processing unit 30, for example, recognizes the inspection part by pattern matching and acquires the position information of the inspection part. The image processing unit 30, for example, acquires the position coordinates of the contour shape of the component P, the geometric center of the component P, individual parts such as the leads of the component P, the label attached to the component P, etc. as position information, or acquires the distances and mounting angles of a plurality of components P. Also, the image processing unit 30 can calculate the position coordinates of each axis direction of the X, Y, and Z of the object 2 from a plurality of images captured by changing the irradiation angle of the illumination light to a plurality of angles by the inclined illumination device 16 and the coaxial illumination device 17, and generate a three-dimensional image (stereoscopic image) of the object 2.

[0038] The table control unit 31 outputs a control command to the table drive device 4 to adjust the angle of the table 3.

[0039] The display control unit 32 causes the display device 11 to display the image of the object 2 acquired by the image acquisition unit 29.

[0040] The storage unit 33 stores various information related to the inspection of the object 2 by the inspection device 1. The storage unit 33 stores an inspection program that defines the position of the inspection site and the inspection items on the object 2. Further, the storage unit 33 stores substrate data including information on the substrate CB and the component P that are the object 2. The storage unit 33 stores the image of the object 2 acquired by the image acquisition unit 29. Further, the storage unit 33 stores a correction formula 53 calculated by the calibration process described later. The correction formula 53 is a function for calculating the in-plane position correction amount 54 in the in-plane direction (X-axis direction and Y-axis direction) according to the position of the imaging device 8 in the height direction (Z-axis direction).

[0041] [In-plane position correction amount] As described above, the imaging device 8 can adjust the distance in the optical axis direction from the object 2 by being moved in the height direction (Z-axis direction) by the Z drive unit 23. When imaging, the imaging device 8 is arranged at an imaging height in focus on the inspection site of the component P, and the position in the height direction is adjusted by the Z drive unit 23.

[0042] However, errors related to the assembly of the imaging device 8 to the moving device 9 and errors related to the guiding accuracy (so-called running accuracy) of the guide member in the height direction (Z-axis direction) inevitably occur. Due to these errors, when the imaging device 8 is moved in the height direction, a positional shift of the field of view (field of view range 25) in the in-plane direction (X-axis direction and Y-axis direction) occurs. Therefore, in the embodiment, the inspection device 1 calculates the in-plane position correction amount 54 corresponding to the position in the height direction of the imaging device 8 and corrects the in-plane positional shift of the field of view caused by the movement in the height direction. The inspection device 1 creates a correction formula 53 for calculating the position correction amount 54 by performing a calibration process.

[0043] FIG. 3 is a diagram for explaining calibration processing for obtaining a position correction amount 54. As shown in FIG. 3, the imaging device 8 ideally moves in the height direction along a moving axis A1 parallel to the Z-axis, but due to the above-described error factors, it moves along a moving axis A2 inclined with respect to the moving axis A1. FIG. 3 shows the inclination of the moving axis A2 exaggerated for ease of understanding. The inclination angle of the actual moving axis A2 with respect to the moving axis A1 is very small. When the imaging device 8 moves along the inclined moving axis A2, for example, as shown by the dotted line, as the position of the imaging device 8 in the Z-axis direction changes, the position (XY coordinates) of the imaging device 8 in the XY plane also changes.

[0044] In the calibration process, a jig 40 having a known shape is imaged at a plurality of height positions to obtain a plurality of jig images 50, and the position coordinates of a plurality of reference points RP having different positions in the height direction are obtained from the obtained jig images 50. Based on the change in the position coordinates of the plurality of reference points RP, the in-plane displacement of the visual field range 25 corresponding to the height position of the imaging device 8 is obtained.

[0045] The plurality of reference points RP have known relative positions in the in-plane direction and different positions in the height direction. Thereby, based on the position of any one of the reference points RP in the in-plane direction, it is possible to know how much the relative position in the in-plane direction with respect to the other reference points RP is shifted and shown. The in-plane relative displacement between the plurality of reference points RP represents the in-plane displacement of the visual field range 25. Preferably, the plurality of reference points RP have the same position in the in-plane direction. In this case, the difference in the positions of each reference point RP in the plurality of jig images 50 directly represents the in-plane displacement of the visual field range 25, so that the calculation of the displacement becomes easy.

[0046] The jig 40 has a detection surface 41 capable of obtaining the position coordinates of the reference point RP. The reference point RP is located in the same plane as the detection surface 41. The jig 40 has a plurality of detection surfaces 41 at different height positions in order to detect a plurality of reference points RP having different height positions. The plurality of detection surfaces 41 are provided for each reference point RP.

[0047] The reference point RP may be a specific structure or a marked part provided on the jig 40. The reference point RP may be a specific position calculated from the outer shape of the jig 40. The reference point RP is a position within the same plane as the inspection surface 41. The reference point RP is, for example, a position obtained from the contour shape of the inspection surface 41.

[0048] FIG. 4 is a schematic perspective view showing the appearance of the jig 40 according to the first embodiment. In the first embodiment, as shown in FIG. 4, the jig 40 has a structure in which the cylindrical main body 42 is formed in a stepped shape (circular pyramid shape) such that the diameter gradually decreases as it goes upward (+Z direction).

[0049] The jig 40 has a plurality of inspection surfaces 41 whose positions in the height direction are different from each other and whose center positions in the in-plane direction coincide. In FIG. 4, the jig 40 has an inspection surface 41A, an inspection surface 41B, an inspection surface 41C, an inspection surface 41D, and an inspection surface 41E. The inspection surfaces 41A, 41B, 41C, 41D, and 41E are provided in this order from the -Z direction to the +Z direction. The inspection surface 41E constitutes the upper end surface of the jig 40. Therefore, when viewed from the height direction (Z direction), the inspection surfaces 41A, 41B, 41C, and 41D are in an annular shape, and the inspection surface 41E is in a circular shape. The jig 40 has the inspection surfaces 41A, 41B, 41C, 41D, and 41E, and their center positions in the in-plane direction are the same. Therefore, the plurality of inspection surfaces 41A to 41E are concentrically shaped when viewed from the height direction (see FIG. 5).

[0050] The inspection surface 41A has a diameter D1. The inspection surface 41B has a diameter D2 (<D1). The inspection surface 41C has a diameter D3 (<D2). The inspection surface 41D has a diameter D4 (<D3). The inspection surface 41E has a diameter D5 (<D4). The difference in diameter between adjacent inspection surfaces in the height direction is equal. That is, the widths of the inspection surfaces 41A, 41B, 41C, and 41D, each having an annular shape, are equal to each other. The difference in diameter between adjacent inspection surfaces in the height direction may be such that the contours of the plurality of inspection surfaces 41 can be separately extracted according to the resolution of the image of the imaging device 8.

[0051] FIG. 5 is a schematic diagram showing a jig 40 disposed in the field of view 25 of the imaging device 8. As shown in FIG. 5, the diameter D1 of the inspection surface 41A is smaller than the vertical and horizontal dimensions of the field of view 25. That is, the jig 40 is formed in a planar size such that the entire inspection surface 41 is within the field of view 25.

[0052] With the jig 40 disposed in the field of view 25 of the imaging device 8, the imaging device 8 is moved along the moving axis A2, and jig images 50 are respectively acquired at height positions where the inspection surfaces 41A, 41B, 41C, 41D, and 41E are in focus.

[0053] As shown in FIG. 3, for the inspection surface 41A, a jig image 50A of the inspection surface 41A is acquired at an imaging height Z1 above a predetermined distance corresponding to the focal length DF. For the inspection surface 41B, a jig image 50B of the inspection surface 41B is acquired at an imaging height Z2 above a predetermined distance. For the inspection surface 41C, a jig image 50C of the inspection surface 41C is acquired at an imaging height Z3 above a predetermined distance. For the inspection surface 41D, a jig image 50D of the inspection surface 41D is acquired at an imaging height Z4 above a predetermined distance. For the inspection surface 41E, a jig image 50E of the inspection surface 41E is acquired at an imaging height Z5 above a predetermined distance.

[0054] The interval in the height direction of the plurality of reference points RP is larger than the depth of field DOF of the imaging device 8. That is, the height difference H (see FIG. 4) between two adjacent inspection surfaces 41 in the height direction is larger than the depth of field DOF. Therefore, when the imaging device 8 is disposed at the imaging height Z2 where one of the inspection surfaces (for example, the inspection surface 41B) is in focus, the other inspection surfaces (the inspection surface 41A and the inspection surface 41C) adjacent in the height direction are located outside the depth of field DOF and are out of focus. Thereby, misrecognition of other inspection surfaces 41 other than the detection target in image processing is suppressed.

[0055] The image processing unit 30 acquires a reference point RP for each of the obtained jig images 50A, 50B, 50C, 50D, and 50E. In the embodiment, the image processing unit 30 acquires the center point of each of the plurality of inspection surfaces 41 as a plurality of reference points RP. Specifically, the image processing unit 30 extracts the circular contour of each inspection surface by pattern matching, and acquires the center position of the extracted contour as the reference point RP.

[0056] FIG. 6 is an explanatory diagram for explaining the reference point RP to be acquired. The image processing unit 30 acquires the position coordinates of a plurality of reference points RP whose relative positions in the in-plane direction are known to each other and whose positions in the height direction are different from each other from a plurality of jig images 50. In the embodiment, the positions of the plurality of reference points RP in the in-plane direction are the same. Therefore, the image processing unit 30 acquires the position coordinates of a plurality of reference points RP whose positions in the in-plane direction are the same and whose positions in the height direction are different.

[0057] The image processing unit 30 acquires the center position of the contour 42A of the inspection surface 41A in the jig image 50A (imaging height Z1) as the position coordinates 51A of the reference point RP1. The image processing unit 30 acquires the center position of the contour 42B of the inspection surface 41B in the jig image 50B (imaging height Z2) as the position coordinates 51B of the reference point RP2. The image processing unit 30 acquires the center position of the contour 42C of the inspection surface 41C in the jig image 50C (imaging height Z3) as the position coordinates 51C of the reference point RP3. The image processing unit 30 acquires the center position of the contour 42D of the inspection surface 41D in the jig image 50D (imaging height Z4) as the position coordinates 51D of the reference point RP4. The image processing unit 30 acquires the center position of the contour 42E of the inspection surface 41E in the jig image 50E (imaging height Z5) as the position coordinates 51E of the reference point RP5. Note that the jig images 50A to 50E shown in FIG. 6 are, strictly speaking, images of the contours of the inspection surfaces 41 extracted by image recognition from the jig images 50A to 50E. The actual jig images 50A to 50E are images in which each inspection surface 41 is included as shown in FIG. 5 and in which only a specific one of the inspection surfaces 41 is in focus.

[0058] FIG. 7 is a schematic diagram for explaining a method of obtaining the position correction amount 54. FIG. 7(A) is a schematic diagram of the jig 40 viewed from the height direction (Z-axis direction), and FIG. 7(B) is a schematic diagram of the jig 40 viewed from the in-plane direction. The circles in FIG. 7 are the position coordinates 51A, 51B, 51C, 51D, and 51E obtained based on the jig image 50, plotted by overlapping them on the actual jig 40.

[0059] As described above, since the positions of the plurality of reference points RP are the same in the in-plane direction, they are located on the central axis of the jig 40 shown in FIG. 7. On the other hand, when the imaging device 8 moves in the height direction along the inclined moving axis A2, the positions of the obtained position coordinates 51A, 51B, 51C, 51D, and 51E will shift in the in-plane direction according to the inclination of the moving axis A2.

[0060] The image processing unit 30 calculates the in-plane position correction amount 54 corresponding to the height position of the imaging device 8 based on the position coordinates of the plurality of reference points RP. Specifically, the image processing unit 30 obtains a correction formula 53 (see FIG. 2) representing a straight line 52 corresponding to the inclination of the moving axis A2 by linearly approximating the obtained position coordinates 51A, 51B, 51C, 51D, and 51E. By the correction formula 53, the in-plane displacement amount of the point G on the straight line 52 when the imaging device 8 is arranged at an arbitrary imaging height Zn and imaged is calculated. This displacement amount becomes the position correction amount 54 corresponding to the imaging height Zn. The image processing unit 30 stores the obtained correction formula 53 in the storage unit 33.

[0061] In the calibration process, by obtaining the correction formula 53 in this way, it becomes possible to calculate the position correction amount 54 for correcting the in-plane position displacement of the visual field range 25 at an arbitrary imaging height.

[0062] [Position Displacement Correction] In the inspection process, the inspection device 1 calculates the position correction amount 54 corresponding to the height position of the imaging device 8 and corrects the in-plane position displacement of the visual field range 25. Specifically, the inspection device 1 corrects the position information 61 of the inspection part obtained based on the image of the object 2 (inspection image 60) based on the position correction amount 54.

[0063] FIG. 8 is a schematic diagram for explaining position correction in the inspection process. In FIG. 8, as an example, for a component Pa with a small height and a component Pc with a large height dimension, the center positions thereof are obtained as inspection sites. The imaging device 8 images the inspection image 60 of the component Pa at the imaging height Za and images the inspection image 60 of the component Pc at the imaging height Zc.

[0064] The image processing unit 30 acquires the position information 61 of the inspection site of the object 2 based on the inspection image 60 of the object 2 imaged by the imaging device 8. In the example of FIG. 8, the image processing unit 30 acquires the center position coordinates of the component Pa as the position information 61a and acquires the center position coordinates of the component Pc as the position information 61c. At this time, the center positions Ga and Gc obtained from the inspection image 60 include position displacements corresponding to their respective imaging heights.

[0065] The position information 61 is corrected based on the position correction amount 54. For the center position Ga, the image processing unit 30 calculates the position correction amount 54a corresponding to the imaging height Za by the correction formula 53 and corrects the position information 61a. For the center position Gc, the image processing unit 30 calculates the position correction amount 54c corresponding to the imaging height Zc by the correction formula 53 and corrects the position information 61c. As a result, the position information 61a and the position information 61c are calculated as the center positions Qa and Qc with the position displacement removed in the in-plane direction.

[0066] In the example shown in FIG. 7, as the imaging height increases (moves in the +Z direction), the position displacement becomes larger. Therefore, compared with the position displacement amount of the center position Ga of the component Pa, the position displacement amount of the center position Gc of the component Pc becomes larger. By obtaining the position correction amount 54 corresponding to the imaging height, it becomes possible to appropriately acquire the in-plane positions of the inspection sites with different height positions. As a result, generation of a three-dimensional image and distance measurement between inspection sites can be performed with high accuracy. For example, it becomes possible to perform high-precision distance measurement in the in-plane direction between the center positions Qa and Qc with different heights.

[0067] [Position Correction Method of Inspection Device] FIG. 9 is a flowchart showing a position correction method of an inspection apparatus according to an embodiment. The position correction method of the inspection apparatus according to the embodiment is a method for calculating a position correction amount 54 for correcting a positional deviation in the in-plane direction of the field of view that occurs when the imaging device 8 is moved in the height direction. The position correction method of the inspection apparatus according to the embodiment is performed in advance as a calibration process before the inspection is carried out by the inspection apparatus 1.

[0068] In the position correction method of the inspection apparatus, the jig 40 is installed on the support surface 13 of the table 3. The jig 40 is supported by the table 3 so that the jig 40 and the imaging device 8 face each other in the vertical direction (height direction) (step S10).

[0069] In the position correction method of the inspection apparatus, the imaging device 8 that images the object 2 in the imaging direction along the height direction with respect to a predetermined plane is arranged at a plurality of positions in the height direction by the moving device 9 to image the jig 40, thereby obtaining a plurality of jig images 50 (step S11).

[0070] As shown in FIG. 3, the imaging position control unit 27 controls the moving device 9 so as to sequentially arrange the imaging device 8 at an imaging height at which each inspection surface 41 of the jig 40 having a known dimension can be imaged, based on the height position of each inspection surface 41. The imaging control unit 28 controls the imaging device 8 to image the corresponding inspection surface 41 at each imaging height. The illumination control unit 26 controls the illumination device 5 to irradiate illumination light in accordance with the imaging timing of the imaging device 8. The image acquisition unit 29 acquires the jig images 50 imaged at each imaging height. Thereby, the jig image 50A of the inspection surface 41A, the jig image 50B of the inspection surface 41B, the jig image 50 of the inspection surface 41C, the jig image 50D of the inspection surface 41D, and the jig image 50E of the inspection surface 41E are acquired.

[0071] Next, position coordinates of a plurality of reference points RP whose in-plane relative positions along a predetermined plane are known to each other and whose positions in the height direction are different are acquired from the plurality of jig images 50 (step S12). The image processing unit 30 acquires the plurality of jig images 50 from the image acquisition unit 29 and acquires the position coordinates of the reference points RP in each of the jig images 50. In the first embodiment, as shown in FIG. 6, the image processing unit 30 acquires the center points of each of the plurality of inspection surfaces 41 as the position coordinates of the plurality of reference points RP.

[0072] The position correction method of the inspection apparatus calculates an in-plane position correction amount 54 corresponding to the position in the height direction of the imaging apparatus 8 based on the position coordinates of the plurality of reference points RP (step S13). The image processing unit 30 obtains a correction formula 53 representing a straight line 52 corresponding to the movement axis A2 of the imaging apparatus 8 by linearly approximating the acquired position coordinates 51A, 51B, 51C, 51D, and 51E. The position correction amount 54 when the imaging apparatus 8 is disposed at an arbitrary height position is calculated by the correction formula 53. The image processing unit 30 stores the acquired correction formula 53 in the storage unit 33.

[0073] [Inspection method] FIG. 10 is a flowchart showing an inspection method according to the embodiment. The object 2 is placed on the support surface 13 of the table 3. The object 2 is supported by the table 3 such that the object 2 and the imaging apparatus 8 face each other (step S20).

[0074] The inspection apparatus 1 acquires an inspection image 60 of the object 2 (step S21). When the object 2 is larger than the visual field range 25 of the imaging apparatus 8, the inspection apparatus 1 performs divided imaging of the object 2. The imaging position control unit 27 controls the moving device 9 so as to move the imaging device 8 to individual imaging positions in order based on the substrate data of the substrate CB which is the object 2. At this time, the imaging position control unit 27 controls the moving device 9 so as to position the imaging device 8 at an imaging height at which the inspection site is in focus according to the height dimensions of each part of the object 2 in the substrate data (that is, the height dimension of the component P). The imaging control unit 28 causes the imaging device 8 to capture an inspection image 60 of the object 2 arranged in the visual field range 25 of the imaging device 8. The illumination control unit 26 controls the illumination device 5 to irradiate illumination light in accordance with the imaging timing of the imaging device 8. The image acquisition unit 29 acquires the inspection image 60 from the imaging device 8. The imaging position control unit 27 acquires information on the imaging height of the imaging device 8 when the inspection image 60 is captured by position information acquisition means such as an encoder or a position sensor provided in the Z drive unit 23. The acquired inspection image 60 and the information on the imaging height of the imaging device 8 when the inspection image 60 is captured are stored in the storage unit 33.

[0075] The image processing unit 30 acquires position information 61 of the inspection site of the object 2 based on the inspection image 60 (step S22). The image processing unit 30 recognizes the inspection site in the image by, for example, pattern matching, and acquires the position information 61 of the recognized inspection site. The template of the inspection site used for pattern matching is created in advance and stored in the storage unit 33. At this time, the acquired position information 61 includes an in-plane positional deviation corresponding to the imaging height of the imaging device 8 when the inspection image 60 is captured.

[0076] The image processing unit 30 corrects the position information 61 of the inspection site according to the in-plane position correction amount 54 corresponding to the height direction position of the imaging device 8 (step S23). The image processing unit 30 calculates the in-plane position correction amount 54 corresponding to the imaging height according to the imaging height of the imaging device 8 when the inspection image 60 is captured and the correction formula 53 obtained by the calibration process. The image processing unit 30 corrects the position information 61 of the inspection site included in the inspection image 60 according to the calculated position correction amount 54. For each inspection image 60 obtained by dividing and imaging the object 2, the image processing unit 30 calculates the position correction amount 54 corresponding to the imaging height of the imaging device 8 when the inspection image 60 is captured, and corrects the position information 61 of the inspection site included in the inspection image 60 respectively.

[0077] The position information 61 of each inspection site of the object 2 is corrected by the position correction amount 54 corresponding to the imaging height of each inspection site. As a result, the error caused by the positional deviation of the visual field range 25 in the position information 61 of each inspection site of the object 2 is removed.

[0078] [Computer System] FIG. 11 is a block diagram showing a computer system 1000 according to an embodiment. The above-described control device 10 includes the computer system 1000. The computer system 1000 has a processor 1001 such as a CPU, a main memory 1002 including a non-volatile memory such as a ROM and a volatile memory such as a RAM, a storage 1003, and an interface 1004 including an input / output circuit. The functions of the control device 10 are stored in the storage 1003 as a computer program. The processor 1001 reads the computer program from the storage 1003 and expands it in the main memory 1002, and executes the above-described processing according to the computer program. Note that the computer program may be distributed to the computer system 1000 via a network.

[0079] According to the above-described embodiments, the computer program causes the computer system 1000 to execute steps of: acquiring a plurality of jig images 50 by arranging the imaging device 8 at a plurality of positions in the height direction by the moving device 9 and imaging the jig 40; acquiring the position coordinates of a plurality of reference points RP from the plurality of jig images 50; and calculating an in-plane position correction amount 54 corresponding to the position in the height direction of the imaging device 8 based on the position coordinates of the plurality of reference points RP.

[0080] [Effect] As described above, according to the first embodiment, the image processing unit 30 acquires a plurality of jig images 50 obtained by imaging the jig 40 with the imaging device 8 arranged at a plurality of positions in the height direction (Z direction), and from the plurality of jig images 50, acquires the position coordinates of a plurality of reference points RP whose relative positions in the in-plane direction (X direction and Y direction) are known to each other and whose positions in the height direction are different. Based on the position coordinates of the plurality of reference points RP, an in-plane position correction amount 54 corresponding to the position in the height direction of the imaging device 8 is calculated. Thereby, from the change in the relative positional relationship of the plurality of reference points RP, the in-plane positional deviation corresponding to the position in the height direction of the imaging device 8 can be grasped, and the in-plane position correction amount 54 for correcting the in-plane positional deviation of the visual field range 25 corresponding to the position in the height direction of the imaging device 8 can be obtained. By using the position correction amount 54, the in-plane positional deviation of the visual field (visual field range 25) accompanying the movement of the imaging device 8 in the height direction can be corrected.

[0081] In the first embodiment, the image processing unit 30 acquires the position coordinates of a plurality of reference points RP that have the same in-plane position and different positions in the height direction. In this case, since the position coordinates of the plurality of reference points RP in the in-plane direction are the same, the deviation of the position coordinates of the reference point RP obtained from each jig image 50 directly represents the in-plane positional deviation of the visual field (visual field range 25). Therefore, the position correction amount 54 can be easily obtained.

[0082] The inspection device 1 includes a jig 40 having a plurality of inspection surfaces 41 with different positions in the height direction and the same center position in the in-plane direction. The image processing unit 30 acquires the center points of each of the plurality of inspection surfaces 41 as a plurality of reference points RP. In this way, by obtaining the center point from the contour shape of the inspection surface 41, the reference point RP can be easily and accurately obtained.

[0083] The plurality of inspection surfaces 41 of the jig 40 are concentric circles when viewed from the height direction. That is, each inspection surface 41 has a circular contour. Since all points of the circular contour serve as samples for calculating the reference point RP, the number of sample points can be increased, and as a result, the reference point RP can be obtained with high accuracy.

[0084] The interval in the height direction of the plurality of reference points RP is larger than the depth of field DOF of the imaging device 8. As a result, in the jig image 50 for obtaining one reference point RP, the structure for obtaining other reference points RP is out of focus. Therefore, when identifying one reference point RP from the jig image 50 by image processing, the information of other reference points RP can be effectively excluded, and thus the position coordinates of the reference point RP can be accurately obtained.

[0085] The image processing unit 30 acquires the position information 61 of the inspection part of the object based on the image of the object 2 captured by the imaging device 8, and corrects the position information 61 based on the position correction amount 54. In this way, the in-plane displacement of the field of view (field of view range 25) accompanying the movement of the imaging device 8 in the height direction can be eliminated, and the position information 61 of the inspection part can be accurately obtained. Also, since the position information 61 obtained from the image is corrected instead of correcting the in-plane position of the imaging device 8 based on the position correction amount 54, it is possible to suppress the complication of the movement control of the imaging device 8.

[0086] According to the position correction method of the inspection apparatus 1 according to the first embodiment, an imaging device 8 that images an object in an imaging direction along the height direction with respect to a predetermined plane is arranged at a plurality of positions in the height direction by a moving mechanism to image a jig 40, thereby obtaining a plurality of jig images 50; obtaining the position coordinates of a plurality of reference points RP whose relative positions in the in-plane direction along the predetermined plane are known to each other and whose positions in the height direction are different from the plurality of jig images 50; and calculating an in-plane position correction amount 54 corresponding to the position in the height direction of the imaging device 8 based on the position coordinates of the plurality of reference points RP. Thereby, from the change in the relative positional relationship of the plurality of reference points RP, the in-plane positional deviation of the visual field (visual field range 25) corresponding to the position in the height direction of the imaging device 8 can be grasped, and the position correction amount 54 for correcting this positional deviation can be obtained. By using the position correction amount 54, the in-plane positional deviation of the visual field (visual field range 25) accompanying the movement of the imaging device 8 in the height direction can be corrected.

[0087] [Second Embodiment] The second embodiment will be described. In the following description, the same or equivalent components as those in the above-described first embodiment are denoted by the same reference numerals, and the description of those components is simplified or omitted.

[0088] In the above first embodiment, the jig 40 having a structure in which the main body portion 42 of the cylinder is formed in a stepped shape (circular pyramid shape) such that the outer diameter gradually decreases as it goes upward (+Z direction) was exemplified. In this second embodiment, an example in which a plurality of jigs 140 that can be stacked in the height direction are used is shown.

[0089] FIG. 12 is a schematic side view showing a plurality of jigs 140 according to the second embodiment. FIG. 13 is a schematic diagram for explaining a method of obtaining reference points RP of a plurality of jigs 140 according to the second embodiment. In the second embodiment, the configuration of the inspection apparatus 1 other than the jig 140 is the same as that in the first embodiment.

[0090] As shown in FIG. 12, the inspection apparatus 1 includes a plurality of jigs 140 that can be stacked on top of each other in the height direction. In the example of FIG. 12, the plurality of jigs 140 includes a first jig 141, a second jig 142, and a third jig 143. In the second embodiment, a reference point RP can be obtained one by one from each of the plurality of jigs 140. Therefore, in FIG. 12, three points, i.e., a reference point RP11, a reference point RP12, and a reference point RP13, are obtained from the three jigs 140 of the first jig 141, the second jig 142, and the third jig 143. The number of jigs 140 is arbitrary as long as it is plural. The number of jigs 140 may be two or four or more. The larger the number of jigs 140, the larger the number of reference points RP, and thus it is possible to improve the accuracy of the position correction amount 54 calculated based on the position coordinates of the reference points RP.

[0091] The plurality of jigs 140 are used stacked in the height direction in the calibration process. In the example of FIG. 12, the first jig 141 is used alone (stacking number = 0). The second jig 142 is stacked on the first jig 141. In this case, the stacking number = 1. The third jig 143 is stacked on the second jig 142 in the laminate of the first jig 141 and the second jig 142. In this case, the stacking number = 2. By stacking, the reference points RP at different height positions can be arranged at the top of the jig 140. The image processing unit 30 acquires the position coordinates of the plurality of reference points RP from the plurality of jig images 50 captured with different stacking numbers of the jigs 140. Thereby, a plurality of reference points RP with different positions in the height direction can be obtained.

[0092] At least a part of the plurality of jigs 140 has a base portion 151, a protrusion 153 provided on one surface 152 of the base portion 151 and detected as a reference point RP, and a recess 155 provided on the other surface 154 of the base portion 151 into which the protrusion 153 is inserted. One surface 152 of the base portion 151 is the upper surface of the base portion 151, and the other surface 154 of the base portion 151 is the lower surface of the base portion 151. In FIG. 12, the first jig 141, the second jig 142, and the third jig 143 all have a base portion 151 and a protrusion 153. The second jig 142 and the third jig 143 have a recess 155. Note that the first jig 141 does not have a recess 155.

[0093] The base portion 151 has a flat plate shape. The planar shape of the base portion 151 is not particularly limited. The base portion 151 may have a circular shape, a polygonal shape, or any other arbitrary shape in a plan view. The base portion 151 may be larger than the visual field range 25 of the imaging device 8 in a plan view. In the first embodiment, an example is shown in which the entire jig 40 fits within the visual field range 25 of the imaging device 8 in a plan view in order to acquire the contour shape of the inspection surface 41. However, in the second embodiment, since the reference point RP is acquired from the protruding portion 153, the size of the base portion 151 is not limited. In the example of FIG. 12, among the plurality of jigs 140, the lower jigs have larger base portions 151. The base portion 151A of the first jig 141 is larger than the base portion 151B of the second jig 142, and the base portion 151B of the second jig 142 is larger than the base portion 151C of the third jig 143. Therefore, when the plurality of jigs 140 are stacked, the base portion 151 portions form a pyramid shape.

[0094] The protruding portion 153 is integrally formed with the base portion 151. The protruding portion 153 is provided so as to rise from one surface 152 which is the upper surface of the base portion 151. The protruding portion 153 has a tapered shape in which the outer dimensions become smaller toward the tip end. The protruding portion 153 has a tip end portion with an area smaller than that of the base end portion connected to the base portion 151. When the jig 140 is imaged, the tip end portion of the protruding portion 153 faces upward of the jig 140. The tip end portion of the protruding portion 153 becomes the reference point RP in the jig image 50. The tip end portion of the protruding portion 153 preferably has a shape suitable for image recognition. The tip end portion of the protruding portion 153 is, for example, in the shape of a flat surface. The planar shape of the tip end portion of the protruding portion 153 is not particularly limited and may have a circular shape, a polygonal shape, or any other arbitrary shape. The tip end portion of the protruding portion 153 has, for example, a circular shape in a plan view. The size (area) of the tip end portion of the protruding portion 153 is preferably as small as possible within a range where image recognition is possible in the jig image 50 from the viewpoints of processing accuracy and recognition accuracy. The protruding portion 153 is formed to have a size such that at least the tip end portion fits within the visual field range 25 of the imaging device 8.

[0095] In the example of FIG. 12, each protruding portion 153 of the plurality of jigs 140 has the same shape. Each protruding portion 153 of the plurality of jigs 140 may have a different shape from each other. The height dimension of the protruding portion 153 is, for example, larger than the depth of field DOF of the imaging device 8. In this case, when focusing on the tip of the protruding portion 153, the base 151 will be out of focus, so only the tip of the protruding portion 153 can be easily recognized by image recognition.

[0096] The concave portion 155 is integrally formed with the base 151. The concave portion 155 is recessed from the other surface 154, which is the lower surface of the base 151, toward the one surface 152. The concave portion 155 provides an accommodation space for accommodating the protruding portion 153 of the jig disposed on the lower side when the plurality of jigs 140 are stacked. Therefore, the concave portion 155 is not provided in the base 151A of the first jig 141 disposed at the lowermost stage. When the plurality of jigs 140 are stacked, the protruding portion 153 of the jig disposed on the lower side is accommodated in the concave portion 155 of the jig disposed on the upper side. The stacking of the jigs 140 is realized by installing the base 151 of the upper jig on the one surface 152 of the base 151 of the lower jig.

[0097] At least a part of the inner surface of the recess 155 functions as a positioning portion for overlapping jigs by coming into contact with the protrusion 153. In FIG. 12, the recess 155 has a concave shape corresponding to the outer shape of the protrusion 153. When a plurality of jigs 140 are stacked, the surface of the protrusion 153 of the jig disposed on the lower side comes into contact with the inner surface of the recess 155 of the jig disposed on the upper side, thereby aligning the in-plane directions of the plurality of jigs 140. The recess 155 is provided at a position directly below the protrusion 153. Therefore, when a plurality of jigs 140 are stacked, the positions of the respective protrusions 153 in the in-plane direction coincide with each other when the protrusions 153 fit into the recesses 155. Therefore, also in the second embodiment, as in the first embodiment, the positions of the plurality of reference points RP in the in-plane direction are the same. In one example, the protrusion 153 has a conical shape, and the recess 155 has a conical concave shape (mortar shape). In this case, the inner surface of the recess 155 becomes a guide surface for guiding the protrusion 153, and the protrusion 153 can be accurately arranged at an appropriate position. Note that a positioning structure may be provided at a position other than the recess 155 of the base portion 151. In that case, the recess 155 only needs to be able to accommodate the protrusion 153 of the lower jig, and the recess 155 may be formed so as not to come into contact with the protrusion 153.

[0098] In the calibration process, as shown in FIG. 13, jig images 50 are captured while varying the number of stacked jigs 140. When each jig image 50 is captured, the imaging device 8 is arranged at an imaging height at which the tip of the protrusion 153 exposed on the uppermost surface of the jig 140 is in focus.

[0099] First, as shown in FIG. 13(A), a jig image 50 with a stacking number = 0 is acquired by the first jig 141. The reference point RP11 is at the height position of the tip of the protrusion 153 of the first jig 141. The imaging device 8 captures a jig image 50 for acquiring the position coordinates of the reference point RP11 at an imaging height Z11 corresponding to the focal length DF with respect to the tip of the protrusion 153.

[0100] Next, as shown in FIG. 13(B), a jig image 50 with a stacking number = 1 is acquired by the laminate of the first jig 141 and the second jig 142. The reference point RP12 is at the height position of the tip of the protrusion 153 of the second jig 142. The imaging device 8 images a jig image 50 for acquiring the position coordinates of the reference point RP12 at an imaging height Z12 that is a predetermined distance above the tip of the protrusion 153 of the second jig 142 according to the focal length DF.

[0101] Next, as shown in FIG. 13(C), a jig image 50 with a stacking number = 2 is acquired by the laminate of the first jig 141, the second jig 142, and the third jig 143. The reference point RP13 is at the height position of the tip of the protrusion 153 of the third jig 143. The imaging device 8 images a jig image 50 for acquiring the position coordinates of the reference point RP13 at an imaging height Z13 that is a predetermined distance above the tip of the protrusion 153 of the third jig 143 according to the focal length DF.

[0102] From the plurality of jig images 50 thus acquired, the image processing unit 30 acquires the position coordinates of a plurality of reference points RP that have the same in-plane position and different height positions. As a result, the in-plane positional deviation of the visual field (visual field range 25) is reflected in the deviation of the position coordinates of the plurality of reference points RP. The image processing unit 30 acquires a correction formula 53 based on the position coordinates of each reference point RP. The image processing unit 30 can calculate an in-plane position correction amount 54 at an arbitrary imaging height using the correction formula 53.

[0103] Note that when the thicknesses (heights of the reference points RP) of the bases 151 of the first jig 141, the second jig 142, and the third jig 143 are different, jig images 50 may be acquired respectively when the second jig 142 is stacked on the first jig 141 and when the third jig 143 is stacked on the first jig 141.

[0104] [Effect] As described above, according to the second embodiment, similar to the first embodiment, from the change in the relative positional relationship of the plurality of reference points RP, the in-plane positional deviation of the visual field (visual field range 25) corresponding to the position in the height direction of the imaging device 8 can be grasped, and a position correction amount 54 for correcting this positional deviation can be obtained. By using the position correction amount 54, the in-plane positional deviation of the visual field (visual field range 25) accompanying the movement of the imaging device 8 in the height direction can be corrected.

[0105] Further, in the second embodiment, the inspection device 1 includes a plurality of jigs 140 that can be stacked in the height direction, and the image processing unit 30 acquires the position coordinates of the plurality of reference points RP from a plurality of jig images 50 captured with different stacking numbers of the jigs 140. Thereby, unlike the case of acquiring a plurality of reference points RP from a single jig, a portion for detecting the reference point RP can be individually provided for the plurality of jigs 140. Therefore, the manufacturing difficulty of the jig 140 can be alleviated.

[0106] Further, in the second embodiment, at least a part of the plurality of jigs 140 has a base portion 151, a protrusion portion 153 provided on one surface 152 of the base portion 151 and detected as a reference point RP, and a recess portion 155 provided on the other surface 154 of the base portion 151 into which the protrusion portion 153 is inserted. Thereby, since the reference point RP may be detected from the portion of the protrusion portion 153, restrictions on the shape and dimensions of the base portion 151 can be eliminated. For example, since the base portion 151 can be made larger than the visual field range 25 of the imaging device 8, the manufacturing difficulty of the jig 140 can be alleviated, and the stability when installing the jig 140 can be improved. Further, by providing the recess portion 155, even in a configuration where the protrusion portion 153 is provided, a plurality of reference points RP having different positions in the height direction can be detected simply by stacking the plurality of jigs 140.

[0107] Other effects of the second embodiment are the same as those of the first embodiment described above.

[0108] [Other Embodiments] In the above-described embodiments, an example was shown in which a correction formula 53 representing a straight line 52 corresponding to the moving axis of the imaging device 8 was obtained from the position coordinates of each reference point RP, but the present invention is not limited to this. For example, instead of obtaining the correction formula 53, a conversion table for converting the position coordinates in the height direction (imaging height) of the imaging device 8 into the in-plane position correction amount 54 may be obtained. Without using the correction formula 53 or the conversion table, when the position coordinates in the height direction (imaging height) of the imaging device 8 are given, the position correction amount 54 may be directly calculated using the position coordinates of each reference point RP.

[0109] In the above-described embodiments, the difference H in height between two detection surfaces adjacent in the height direction is made larger than the depth of field DOF of the imaging device 8, so that the interval in the height direction of the plurality of reference points RP is made larger than the depth of field DOF of the imaging device 8, but the present invention is not limited to this. When the contours of the respective detection surfaces 41 can be sufficiently distinguished even if a plurality of detection surfaces 41 are imaged in the same jig image 50, the interval in the height direction of the plurality of reference points RP may be equal to or less than the depth of field DOF of the imaging device 8. For example, in FIG. 5, if the difference in diameter between the respective detection surfaces 41 is made sufficiently large, the individual detection surfaces 41 can be accurately identified.

[0110] In the above-described embodiments, the imaging device 8 is moved in the XY plane by the moving device 9. The table 3 may be moved in the XY plane, or both the table 3 and the imaging device 8 may be moved in the XY plane. It is only necessary that the imaging device 8 be movable in the height direction, and regarding the in-plane direction, either the table 3 or the imaging device 8 may be movable.

Explanation of Reference Numerals

[0111] 1…Inspection device, 2…Object, 3…Table, 4…Table drive device, 5…Illumination device, 6…Optical system, 7…Image sensor, 8…Imaging device, 9…Moving device, 10…Control device, 11…Display device, 13…Support surface, 14…Actuator, 15…Base member, 16…Oblique illumination device, 17…Coaxial illumination device, 18…Light source, 18A…First light source, 18B…Second light source, 18C…Third light source, 19…Support member, 20…Incident surface, 21…Light source, 22…Support member, 23…Z drive unit, 24…XY drive unit, 25…Field of view, 26…Illumination control unit, 27…Imaging position control unit, 28…Imaging control unit, 29…Image acquisition unit, 30…Image processing unit, 31…Table control unit, 32…Display control unit, 33…Memory unit, 40…Fixture, 41, 41A, 41B, 41C, 41D, 41E…Inspection surface, 42…Main body, 42A, 42B, 42C, 42D, 42E…Contour, 50, 50A, 50B, 50C, 50D, 50E…Fixture image, 51A, 51B, 51C, 51D, 51E…Position coordinates, 52…Straight line, 53…Correction formula, 54, 54a, 54c…Position correction amount, 60…Inspection image, 61, 61a, 61c…Position information, 140…Fixture, 141…First fixture, 142…Second fixture, 143…Third fixture, 151, 151A, 151B, 151C…Base, 152…One side, 153…Protrusion, 154…The other side, 155…Recess, 1000…Computer system, 1001…Processor, 1002…Main memory, 1003…Storage, 1004…Interface, A1, A2…Moving axis, AX…Optical axis, CB…Substrate, D1, D2, D3, D4, D5…Diameter, DF…Focal length, DOF…Depth of field, Ga, Gc, Qa, Qc…Center position, P, Pa, Pb, Pc…Parts, RP, RP1, RP2, RP3, RP4, RP5, RP11, RP12, RP13…Reference point.

Claims

1. An imaging device that images an object in an imaging direction along the height direction with respect to a predetermined plane, a moving device that moves the imaging device in the height direction, an image processing unit that processes an image captured by the imaging device, and comprising: The image processing unit: acquires a plurality of jig images obtained by imaging a jig with the imaging device arranged at a plurality of positions in the height direction, acquires position coordinates of a plurality of reference points whose relative positions in the in-plane direction along the predetermined plane are known to each other and whose positions in the height direction are different from the plurality of jig images, calculates a position correction amount in the in-plane direction corresponding to the position of the imaging device in the height direction based on the position coordinates of the plurality of reference points, An inspection device.

2. The image processing unit acquires position coordinates of a plurality of reference points whose positions in the in-plane direction are the same and whose positions in the height direction are different. The inspection device according to claim 1.

3. The jig includes a plurality of inspection surfaces whose positions in the height direction are different from each other and whose center positions in the in-plane direction coincide, The image processing unit acquires the center points of each of the plurality of inspection surfaces as the plurality of reference points. The inspection device according to claim 2.

4. The plurality of inspection surfaces are concentric when viewed from the height direction. The inspection device according to claim 3.

5. The jig includes a plurality of jigs that can be stacked on top of each other in the height direction, The image processing unit acquires the position coordinates of the plurality of reference points from the plurality of jig images captured by varying the number of stacked jigs. The inspection device according to claim 2.

6. At least a part of the plurality of jigs has a base, a protrusion provided on one surface of the base and detected as the reference point, and a recess provided on the other surface of the base into which the protrusion is inserted. The inspection device according to claim 5.

7. The interval in the height direction of the plurality of reference points is larger than the depth of field of the imaging device. The inspection device according to any one of claims 1 to 6.

8. The image processing unit: acquires position information of an inspection part of the object based on an image of the object captured by the imaging device, corrects the position information based on the position correction amount. The inspection device according to any one of claims 1 to 6.

9. A step of acquiring a plurality of jig images by arranging an imaging device that images an object in an imaging direction along the height direction with respect to a predetermined plane at a plurality of positions in the height direction by a moving device and imaging a jig; A step of acquiring position coordinates of a plurality of reference points whose relative positions in the in-plane direction along the predetermined plane are known to each other and whose positions in the height direction are different from the plurality of jig images; A step of calculating a position correction amount in the in-plane direction corresponding to the position of the imaging device in the height direction based on the position coordinates of the plurality of reference points; and A position correction method for an inspection device.

Images