Inspection device

Abstract

Provided is an inspection device capable of reducing a blind area of illumination light on an imaging object and improving measurement accuracy. An inspection device (10) is provided with: a first imaging unit (21) for imaging an object to be inspected (12) from the vertical direction; a plurality of reflecting plates (230a-230c) which are dome-shaped, are disposed between the first imaging unit (21) and the object to be inspected (12), and have openings (233-236) on the first imaging unit (21) side and the object to be inspected (12) side, respectively; a plurality of light sources (23a-23c) which are in a ring shape and which illuminate each of the reflecting plates (230a-230c); and an inspection device (a second imaging unit (22), a projection unit (24)) that is positioned outside the reflecting plates (230a-230c) and is capable of imaging the object to be inspected (12) or irradiating the object to be inspected with light, the optical axis of the inspection device being disposed so as to pass through the through-holes (237, 238) provided in the reflecting plates (230a-230c).

Description

Technical Field

[0001] The invention relates to an inspection device. Background Art

[0002] In an inspection device that images an object to be inspected, such as a substrate on which electronic components are mounted, and uses the image data obtained by the image capture to inspect the appearance of the object to be inspected, there is the following structure: as a method of illuminating the imaging object, i.e., the imaging object, a lighting unit having a dome-shaped reflector plate arranged so as to cover the imaging object from a vertical direction is used, so that light from a light source is reflected by the reflector plate and irradiates the imaging object with illumination light (for example, refer to patent document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-237034 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the case of the above-mentioned structure, in addition to the main camera unit for photographing the object from a vertical direction, there are also inspection equipment such as an inclined camera unit for photographing the object from an inclined direction, a projection unit for projecting pattern stripes onto the object, etc. To this end, it is necessary to open a through hole in the reflector plate of the lighting unit to allow the light path to pass through. However, if the diameter of the through hole becomes larger, an area that is not irradiated with the illumination light (this area is called a "blind spot") is generated in the object, resulting in a problem of reduced measurement accuracy.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an inspection device capable of reducing a blind spot of illumination light on an imaging object and improving measurement accuracy.

[0009] Solutions for solving problems

[0010] In order to solve the above-mentioned problem, the inspection device involved in the present invention comprises: a main camera part, which is used to photograph the object to be photographed from a vertical direction; a plurality of reflective plates, which are dome-shaped and are arranged between the main camera part and the object to be photographed, and have openings on the reflective plates on the side close to the main camera part and the side close to the object to be photographed, respectively; a plurality of light sources, which are ring-shaped and illuminate each of the reflective plates; and an inspection device, which is located on the outside of the reflective plate and can photograph or irradiate the object to be photographed, wherein the optical axis of the inspection device is arranged to pass through a through hole provided on the reflective plate.

[0011] Effects of the Invention

[0012] According to the inspection device of the present invention, it is possible to reduce the blind spot of the illumination light on the imaging object and improve the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an explanatory diagram for explaining the structure of the inspection device.

[0014] Figure 2 1 and 2 are explanatory diagrams for explaining the structure of the illumination unit, wherein (a) is a plan view viewed from the first imaging unit side, and (b) is an AA cross-sectional view in (a).

[0015] Figure 3 It is an explanatory diagram showing the arrangement of the illumination section, the first imaging section, the second imaging section, and the projection section in the imaging unit.

[0016] Figure 4 This is an explanatory diagram for explaining the relationship between the inspection equipment and the through hole.

[0017] Figure 5 These are explanatory diagrams for explaining the relationship between the projection angle of the illumination unit and the detection of its reflected light. (a) shows the projection angle of each light source of the illumination unit, and (b) shows an example of the state of the inspection surface of the inspection object. DETAILED DESCRIPTION

[0018] Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 The structure of the inspection device 10 involved in the present embodiment is described below. The inspection device 10 is an inspection device that uses the inspection object image data obtained by photographing the inspection object 12 to inspect the inspection object 12. The inspection object 12 is, for example, an electronic circuit substrate on which many electronic components are installed. The inspection device 10 determines whether the installation state of the electronic components is good based on the inspection object image data. Usually, the inspection is performed on each component with respect to multiple inspection items. The inspection item is the item that needs to be determined whether it is good or not. The inspection items include, for example, inspection items about the configuration of the component, such as missing parts, positional offset, polarity inversion, etc., and inspection items about the connection between the component and the substrate, such as welding status and floating pins of the component.

[0019] The inspection device 10 is configured to include: an inspection platform 14 for holding an inspection object 12; an imaging unit 20 for illuminating and photographing the inspection object 12; an XY table 16 for moving the imaging unit 20 relative to the inspection platform 14; and a control unit 30 for controlling the actions of the imaging unit 20 and the XY table 16. Figure 1As shown, the inspection object loading surface of the inspection platform 14 is set to the XY plane, and the direction perpendicular to the loading surface (i.e., the shooting direction of the camera unit 20 (the shooting axis of the first camera unit 21 (the optical axis direction of the optical system of the first camera unit 21)) is set to the Z direction.

[0020] The camera unit 20 is mounted on a movable platform (not shown) of the XY table 16, and can be moved in the X direction and the Y direction by the XY table 16. The XY table 16 is, for example, a so-called H-type XY table. Therefore, the XY table 16 includes: a Y drive unit that moves the movable platform in the Y direction along a Y-direction guide extending in the Y direction; and two X-direction guides and two X-drive units that are configured to support the Y-direction guide at both ends and can move the movable platform and the Y-direction guide in the X direction. In addition, the XY table 16 may also include a Z moving mechanism that moves the camera unit 20 in the Z direction, and may also include a rotating mechanism that rotates the camera unit 20. The inspection device 10 may also include an XY table that can move the inspection platform 14, in which case the XY table 16 that moves the camera unit 20 may also be omitted. In addition, the X drive unit and the Y drive unit may use a linear motor or a ball screw.

[0021] The imaging unit 20 is configured to include: a first imaging unit 21, which is a main imaging unit for photographing the object to be inspected 12 as an imaging object from a vertical direction; a second imaging unit 22, which is an oblique imaging unit for photographing the object to be inspected 12 from an oblique direction; an illumination unit 23, which illuminates the object to be inspected 12; and a projection unit 24, which projects pattern stripes for three-dimensional measurement onto the object to be inspected 12. In the inspection device 10 involved in this embodiment, the first imaging unit 21, the second imaging unit 22, the illumination unit 23, and the projection unit 24 are configured as an integrated imaging unit 20, and in the integrated imaging unit 20, the relative positions of the first imaging unit 21, the second imaging unit 22, the illumination unit 23, and the projection unit 24 are fixed, but each unit can be configured to be relatively movable. In addition, the first imaging unit 21, the second imaging unit 22, the illumination unit 23, and the projection unit 24 can also be configured separately and can be moved separately.

[0022] The first camera unit 21 includes an image pickup element that generates two-dimensional image data of an image pickup object and an optical system (e.g., a lens) for imaging the image on the image pickup element. The first camera unit 21 is, for example, a CMOS camera or a CCD camera. The maximum field of view of the first camera unit 21 may also be smaller than the inspection object placement area of ​​the inspection platform 14. In this case, the first camera unit 21 captures the entirety of the inspection object 12 in a manner that is divided into a plurality of partial images. The control unit 30 controls the XY worktable 16 so that each time the first camera unit 21 captures a partial image and outputs partial image data, the first camera unit 21 moves to the next imaging position. The control unit 30 synthesizes the partial image data to generate overall image data of the inspection object 12.

[0023] In addition, the first imaging unit 21 may include an imaging element that generates a one-dimensional image instead of a two-dimensional imaging element. In this case, the first imaging unit 21 can scan the subject 12 to acquire an entire image of the subject 12 .

[0024] The lighting unit 23 is configured to project illumination light for the first imaging unit 21 and the second imaging unit 22 onto the surface of the object to be inspected 12. The lighting unit 23 includes one or more light sources that emit light of a wavelength or a wavelength range selected from a wavelength range that can be detected by the imaging elements of the first imaging unit 21 and the second imaging unit 22. The illumination light is not limited to visible light, and ultraviolet light, X-rays, etc. may also be used. When a plurality of light sources are provided, each light source is configured to project light of different wavelengths (for example, red, blue, and green) onto the surface of the object to be inspected 12 at different projection angles.

[0025] In the inspection device 10 involved in the present embodiment, the lighting unit 23 includes: a side lighting source (in the present embodiment, composed of an upper light source 23a, a middle light source 23b, and a lower light source 23c); and a reflector 230, which reflects the light emitted from the side lighting sources 23a to 23c to project the lighting light from an oblique direction to the inspection surface of the inspection object 12 (i.e., the surface (XY surface) relative to the camera unit 20) (the details of the side lighting sources 23a to 23c and the reflector 230 will be described later). Here, in the inspection device 10 involved in the present embodiment, the side lighting sources 23a, 23b, and 23c are respectively annular light sources (annular lighting sources), which are configured to surround the optical axis of the first camera unit 21, and project the lighting light obliquely to the inspection surface of the inspection object 12 through the reflector 230. In addition, each of the upper light source 23a, the middle light source 23b and the lower light source 23c as these side illumination sources can also be composed of multiple light sources arranged in a ring shape. In addition, the upper light source 23a, the middle light source 23b and the lower light source 23c are respectively configured to project illumination light at different angles to the inspection surface via the reflector 230.

[0026] In addition, each of the upper light source 23a, the middle light source 23b and the lower light source 23c as the side lighting source can be composed of one annular lighting source or a plurality of annular lighting sources. For example, the upper light source 23a in the side lighting source is configured as one annular lighting unit, and the middle light source 23b and the lower light source 23c can be configured as one integrated annular lighting unit. In addition, the upper light source 23a and the lower light source 23c in the side lighting source can be set as red lighting sources, and the middle light source 23b in the side lighting source can be configured by a green lighting source, a blue lighting source and a red lighting source. In addition, the upper light source 23a and the lower light source 23c can be configured by green and blue lighting sources.

[0027] As described above, in the description of this embodiment, the case of using three light sources (side illumination sources 23a to 23c) that irradiate illumination light to the object to be inspected 12 from different angles is described, but the type (number) of light sources is not limited to three, and it may be two or more than four light sources. For example, in addition to the side illumination sources 23a to 23b, an incident illumination source that irradiates illumination light to the object to be inspected 12 along the optical axis of the first camera unit 21 may be combined. Alternatively, only a few of the side illumination sources 23a to 23c may be used. In addition, any one of the light sources 23a to 23c may be used, and in this case, it may be configured to obtain a monochromatic image generated by a monochromatic light source.

[0028] exist Figure 1 In the figure, for reference, a dotted arrow indicates a light beam emitted from the upper light source 23a among the side illumination sources 23a to 23c, reflected by the reflector 230, projected onto the object 12 to be inspected, and further reflected by the inspection surface of the object 12 to be incident on the first imaging unit 21. In addition, dotted arrows are also used to indicate light emitted from the middle light source 23b, the lower light source 23c, and the projection unit 24 among the side illumination sources, and light incident on the second imaging unit 22. Here, for convenience of explanation, the surface of the object 12 to be inspected is shown as a plane, but in reality, it has an inclination and height depending on the part, like a general object to be inspected.

[0029] In addition, the second camera unit 22 is configured to shoot the inspection surface (substrate surface) of the inspection object 12 from an oblique direction. Similar to the first camera unit 21, the second camera unit 22 is also a CMOS camera or a CCD camera. In addition, in the illustrated embodiment, the second camera unit 22 is provided between the middle light source 23b and the lower light source 23c, but the configuration of the second camera unit 22 is not limited thereto, and for example, the second camera unit 22 may also be provided outside the lower light source 23c.

[0030] In addition, a plurality of second imaging units 22 may be provided around the first imaging unit 21. The plurality of second imaging units 22 are arranged to image the inspection object 12 from different directions. This can reduce the area that is blocked and cannot be imaged due to the height difference of the inspection surface.

[0031] The projection unit 24 projects the pattern onto the inspection surface of the inspection object 12. The inspection object 12 on which the pattern is projected is photographed by the first camera unit 21. In addition, in the illustrated embodiment, the projection unit 24 is provided between the upper light source 23a and the middle light source 23b, but the configuration of the projection unit 24 is not limited thereto, and for example, the projection unit 24 may be provided outside the lower light source 23c.

[0032] The inspection device 10 creates a height map of the inspection surface of the inspection object 12 based on the pattern image data of the inspection object 12 captured in a state where the pattern is projected from the projection unit 24. The control unit 30 detects a local inconsistency of the pattern image with respect to the projection pattern, and obtains the height of the portion based on the local inconsistency. That is, the change of the imaging pattern (the pattern projected onto the inspection object 12 and captured by the first imaging unit 21) with respect to the projection pattern (the pattern projected from the projection unit 24 to the inspection object 12) corresponds to the change in height on the inspection surface.

[0033] Here, the projection pattern is preferably a one-dimensional stripe pattern in which bright lines and dark lines are alternately and periodically repeated. The projection unit 24 is configured to project the stripe pattern onto the inspection surface of the inspection object 12 from an oblique direction. The discontinuity of the height of the inspection surface of the inspection object 12 appears as a shift of the pattern in the stripe pattern image. Therefore, the height difference can be calculated based on the shift amount of the pattern. In the inspection device 10 involved in the present embodiment, the control unit 30 creates a height map by using the PMP (Phase Measurement Profilometry) method of a stripe pattern whose brightness changes according to a sinusoidal curve. In the PMP method, the shift amount of the stripe pattern is equivalent to the phase difference of the sine curve.

[0034] The projection unit 24 is configured to include a pattern forming device, a light source for illuminating the pattern forming device, and an optical system for projecting a pattern onto the inspection surface of the inspection object 12. The pattern forming device can be, for example, a variable pattern forming device that can dynamically generate a desired pattern, such as a liquid crystal display, or a fixed pattern forming device that fixedly forms a pattern on a substrate such as a glass plate. In the case where the pattern forming device is a fixed pattern forming device, it is preferred to make the projection position of the pattern variable by providing a moving mechanism that moves the fixed pattern forming device, or by providing an adjustment mechanism in the optical system for pattern projection. In addition, the projection unit 24 can also be configured to be able to switch between a plurality of fixed pattern forming devices having different patterns.

[0035] A plurality of projection units 24 may be provided around the first imaging unit 21. The plurality of projection units 24 are arranged to project patterns from different projection directions onto the inspection object 12. This can reduce the area where the pattern cannot be projected due to shadows caused by height differences of the inspection surface.

[0036] Figure 1 The control unit 30 shown here uniformly controls the entire device, and is implemented as hardware by a CPU, memory, or other LSI of any computer, or as software by a program loaded into the memory, etc., and functional blocks implemented by their cooperation are drawn here. Therefore, it can be understood by those skilled in the art that these functional blocks can be implemented in various forms by hardware only, software only, or a combination of them.

[0037] exist Figure 1 , an example of the structure of the control unit 30 is shown in FIG. The control unit 30 is configured to include an inspection control unit 31 and a memory 35 as a storage unit. The inspection control unit 31 is configured to include a height measuring unit 32, an inspection data processing unit 33, and an inspection unit 34. In addition, the inspection device 10 includes an input unit 36 ​​for accepting input from a user or other devices, and an output unit 37 for outputting information related to the inspection, and the input unit 36 ​​and the output unit 37 are respectively connected to the control unit 30. The input unit 36 ​​includes, for example, an input component such as a mouse and a keyboard for accepting input from a user, and a communication component for communicating with other devices. The output unit 37 includes a well-known output component such as a display and a printer.

[0038] The inspection control unit 31 is configured to perform various control processes for inspection based on the input from the input unit 36 ​​and the inspection-related information stored in the memory 35. The inspection-related information includes the two-dimensional image data of the object to be inspected 12, the height map of the object to be inspected 12, and the substrate inspection data (inspection data). Before the inspection, the inspection data processing unit 33 uses the two-dimensional image data and the height map of the object to be inspected 12 to ensure that all inspection items are qualified to create the substrate inspection data. The inspection unit 34 performs the inspection based on the created substrate inspection data, and the two-dimensional image data and the height map of the object to be inspected 12 to be inspected.

[0039] Substrate inspection data is inspection data produced for each type of substrate. Substrate inspection data can be said to be a collection of inspection data for each component mounted on the substrate. The inspection data for each component includes the inspection items required for the component, the inspection area on the image related to each inspection item, i.e., the inspection window, and the inspection benchmark as a benchmark for determining whether each inspection item is good. One or more inspection windows are set for each inspection item. For example, in an inspection item for determining whether the welding of a component is good, the same number of inspection windows as the number of welding areas of the component are usually set in a configuration corresponding to the configuration of the welding area. In addition, for inspection items using image data obtained by performing prescribed image processing on the image data of the inspected object, the content of the image processing is also included in the inspection data.

[0040] As the substrate inspection data production process, the inspection data processing unit 33 sets each item of the inspection data to match the substrate. For example, the inspection data processing unit 33 automatically sets the position and size of each inspection window for each inspection item to be suitable for the component layout of the substrate. The inspection data processing unit 33 may also accept user input for a part of the items in the inspection data. For example, the inspection data processing unit 33 may also accept adjustment of the inspection benchmark by the user. The inspection benchmark may also be set using height information.

[0041] The inspection control unit 31 performs video processing on the object to be inspected 12 as a preprocessing for the production of substrate inspection data. For the object to be inspected 12, an object to be inspected that passes all inspection items is used. As described above, while the illumination unit 23 illuminates the object to be inspected 12, the relative movement of the video unit 20 and the inspection platform 14 is controlled, and the first video unit 21 and the second video unit 22 sequentially capture local images of the object to be inspected 12 to obtain local image data, thereby performing video processing. A plurality of local image data are captured in a manner covering the entirety of the object to be inspected 12. The inspection control unit 31 synthesizes these multiple local image data to generate substrate whole-surface image data including the entire inspection surface of the object to be inspected 12. The inspection control unit 31 stores the substrate whole-surface image data in the memory 35.

[0042] In addition, as a preprocessing for making a height map, the inspection control unit 31 controls the relative movement of the camera unit 20 and the inspection platform 14 while projecting a pattern to the inspected object 12 through the projection unit 24, and obtains segmented image data when the pattern is projected by dividing the pattern image of the inspected object 12 through the first camera unit 21 and photographing it in sequence. The projected pattern is preferably a stripe pattern whose brightness changes according to a sine curve based on the PMP method. The inspection control unit 31 synthesizes the segmented image data obtained by photographing to generate image data of the entire inspection surface of the inspected object 12, that is, pattern image data. The inspection control unit 31 stores the pattern image data in the memory 35. In addition, the pattern image data can also be generated for a part of the inspection surface instead of the entire surface.

[0043] The height measuring unit 32 creates a height map of the entire inspection surface of the inspected object 12 based on the camera pattern of the pattern image data. The height measuring unit 32 first obtains the local phase difference between the pattern image data and the reference pattern image data for the entire image, thereby obtaining a phase difference map of the inspection surface of the inspected object 12. The reference pattern image data is a pattern image projected by the projection unit 24 (that is, image data generated by a pattern forming device built into the projection unit 24). The height measuring unit 32 creates a height map of the inspected object 12 based on a reference plane serving as a reference for height measurement and a phase difference map. The reference plane is, for example, the substrate surface of an electronic circuit substrate to be inspected. The reference plane does not have to be a plane, but may be a curved surface reflecting deformations such as warping of the substrate. The reference plane may be pre-specified by user input, or the reference plane may be obtained for each substrate by, for example, a substrate surface height measurement method described later.

[0044] Specifically, the height measuring unit 32 uses each pixel of the camera pattern image data and the pixel of the reference pattern image data corresponding to the pixel to obtain the phase difference of the stripe pattern. The height measuring unit 32 converts the phase difference into height. The local stripe width near the pixel is used for conversion to height. This is to interpolate the situation where the stripe width on the camera pattern image data is different depending on the position. This is because, since the distance from the projection unit 24 is different depending on the position on the inspection surface, even if the stripe width of the reference pattern is constant, the stripe width will change linearly from one end to the other end of the pattern projection area of ​​the inspection surface. The height measuring unit 32 obtains the height from the reference plane based on the converted height and the reference plane, and creates a height map of the inspected object 12.

[0045] The inspection control unit 31 may also create object image data having a height distribution by associating the height information of the height map of the object 12 with each pixel of the two-dimensional image of the object 12. In addition, the inspection control unit 31 may also display the three-dimensional modeling of the object 12 based on the object image data having the height distribution. In addition, the inspection control unit 31 may also display the height distribution on the output unit 37 in a manner superimposed on the two-dimensional object image data. For example, the object image data may also be displayed in color by the height distribution. In addition, in the inspection device 10 involved in the present embodiment, the projection unit 24 and the height measurement processing of the object 12 performed by the projection unit 24 may not be installed.

[0046] Next, in the inspection apparatus 10 according to the present embodiment, a method of illuminating the inspection object 12 by the illumination unit 23 of the imaging unit 20 when the first imaging unit 21 and the second imaging unit 22 acquire image data of the inspection object 12 will be described.

[0047] like Figure 2 and Figure 3 As shown, the lighting unit 23 of the imaging unit 20 has the above-mentioned side illumination sources (upper light source 23a, middle light source 23b and lower light source 23c) and a dome-shaped reflector 230 disposed between the first imaging unit 21 and the object to be inspected 12. The reflector 230 has openings 233 and 236 formed on the first imaging unit 21 side and the object to be inspected 12 side, respectively.

[0048] To explain in more detail, the reflector 230 is divided into three parts, namely, an upper reflector 230a, a middle reflector 230b, and a lower reflector 230c, each of which is dome-shaped, in order from the first camera unit 21 side, and is connected to each other in a manner that the openings 234 and 235 are connected. In addition, in the following description, the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c constituting the reflector 230 are also referred to as divided parts.

[0049] The upper reflector 230a is formed with an opening 233 on the side close to the first imaging unit 21, and a ring-shaped protrusion 231a extending inward is formed at the end close to the inspection object 12, and the inner periphery of the protrusion 231a serves as an opening 234. The inner peripheral surface 232a of the upper reflector 230a serves as a reflection surface for reflecting light, and the upper light source 23a is arranged on the side of the protrusion 231a close to the first imaging unit 21. Therefore, the light emitted from the upper light source 23a illuminates the inner peripheral surface 232a of the upper reflector 230a, and then is reflected on the inner peripheral surface 232a, and is irradiated to the inspection object 12 through the opening 234.

[0050] The middle reflector 230b is formed with an opening 234 on the side close to the first camera unit 21, and a ring-shaped protrusion 231b extending inward is formed at the end close to the inspected object 12, and the inner periphery of the protrusion 231b serves as an opening 235. The inner peripheral surface 232b of the middle reflector 230b serves as a reflection surface for reflecting light. The surface of the protrusion 231a of the upper reflector 230a close to the inspected object 12 is also a part of the inner peripheral surface 232b of the middle reflector 230b, and serves as a reflection surface. In addition, the middle light source 23b is arranged on the side close to the first camera unit 21 of the protrusion 231b of the middle reflector 230b. Therefore, the light radiated from the middle light source 23b illuminates the inner peripheral surface 232b of the middle reflector 230b, and then reflects on the inner peripheral surface 232b, and is irradiated to the inspected object 12 through the opening 235.

[0051] The lower reflector 230c is formed with an opening 235 on the side close to the first camera unit 21, and a ring-shaped protrusion 231c extending inward is formed at the end close to the inspected object 12, and the inner periphery of the protrusion 231c serves as an opening 236. The inner peripheral surface 232c of the lower reflector 230c serves as a reflection surface for reflecting light. The surface of the protrusion 231b of the middle reflector 230b close to the inspected object 12 is also a part of the inner peripheral surface 232c of the lower reflector 230c, and serves as a reflection surface. In addition, the lower light source 23c is arranged on the side close to the first camera unit 21 of the protrusion 231c of the lower reflector 230c. Therefore, the light radiated from the lower light source 23c illuminates the inner peripheral surface 232c of the lower reflector 230c, and then reflects on the inner peripheral surface 232c, and is irradiated to the inspected object 12 through the opening 236.

[0052] also, Figure 3 This is a diagram for explaining the relationship between the side illumination sources 23a to 23c in the illumination unit 23 and the reflector 230, and the relationship between the illumination unit 23 and the first imaging unit 21, the second imaging unit 22, and the projection unit 24. Therefore, in an actual product, for example, the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c may be prepared separately from the light source unit equipped with each of the side illumination sources 23a to 23c, and the illumination unit 23 may be manufactured by assembling them.

[0053] As described above, in the lighting unit 23 of the imaging unit 20 in the inspection device 10 according to the present embodiment, the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c are connected in the vertical direction so that the openings 234 and 235 are connected. That is, since the opening of the upper reflector 230a on the side of the object to be inspected 12 and the opening of the middle reflector 230b on the side of the first imaging unit 21 are the opening 234, the radii thereof are the same size. In addition, since the opening of the middle reflector 230b on the side of the object to be inspected 12 and the opening of the lower reflector 230c on the side of the first imaging unit 21 are the opening 235, the radii thereof are the same size.

[0054] The upper reflector 230a is provided with through holes 237 arranged in a ring shape at intervals so as to surround the opening 233. Moreover, on the outer side of the upper reflector 230a, the projection units 24 as the inspection equipment are arranged in a ring shape so that the optical axis thereof passes through each of the through holes 237. In addition, the following case is shown here: in the X direction and the Y direction, four through holes 237 are formed so as to be arranged opposite to each other with the opening 233 sandwiched therebetween, that is, arranged at intervals of 90°, and four projection units 24 are arranged for each through hole 237, but the number of sets of through holes 237 and projection units 24 is not limited to four, and for example, it may be composed of three sets of through holes 237 and projection units 24 arranged at intervals of 120°, or may be composed of five or more sets of through holes 237 and projection units 24.

[0055] The middle reflector 230b is provided with through holes 238 arranged in a ring shape at intervals so as to surround the upper reflector 230a. Moreover, the second imaging unit 22 as the inspection device is arranged in a ring shape on the outer side of the middle reflector 230b so that its optical axis passes through the through holes 238. In addition, the following case is shown here: four through holes 238 are formed in the X direction and the Y direction so as to face each other, that is, arranged at intervals of 90° with the upper reflector 230a sandwiched therebetween, and four second imaging units 22 are arranged for each through hole 238. However, the number of sets of through holes 238 and second imaging units 22 is not limited to four. For example, it may be composed of three sets of through holes 238 and second imaging units 22 arranged at intervals of 120°, or may be composed of five or more sets of through holes 238 and second imaging units 22.

[0056] In addition, a through hole may be provided in the lower reflector 230c, and the inspection equipment may be arranged in such a manner that the optical axis passes through the through hole. Here, as the inspection equipment, in addition to the second imaging unit 22 and the projection unit 24 as the above-mentioned oblique imaging unit, a specific wavelength irradiation unit for irradiating illumination light of a specific wavelength to the inspected object 12 may be further configured.

[0057] By providing the through holes 237 and 238 in the reflector 230 as described above and disposing the inspection device so that the optical axis passes through these through holes 237 and 238, it is possible to Figure 3 As shown in the figure, the inspection object 12 can be irradiated with pattern stripes or illumination light of a specific wavelength at a different angle relative to the imaging axis of the first imaging unit 21 as the main imaging unit, or the inspection object 12 can be photographed. In addition, the inspection device can be configured such that the closer the configured reflector 230 is to the imaging object side (in the order of the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c), the larger the angle between the imaging axis of the first imaging unit 21 as the main imaging unit and the optical axis of the inspection device. In addition, when the second imaging unit 22 as the tilted imaging unit and the projection unit 24 are configured as the inspection device on the reflector 230, it is desirable to configure the projection unit 24 at a position closer to the first imaging unit 21 as the main imaging unit than the second imaging unit 22. By making the projection angle of the projection unit 24 close to the optical axis of the first imaging unit 21 as the main imaging unit, the portion of the inspection object 12 that becomes a shadow can be reduced. This is particularly effective when the distance between adjacent components is short, such as in chip components.

[0058] In addition, regarding the light sources (the upper light source 23 a , the middle light source 23 b , and the lower light source 23 c ) provided in the illumination unit 23 , it is desirable that the control unit 30 can control the lighting timing and the color of light for each light source.

[0059] In addition, the light sources (upper light source 23a, middle light source 23b, and lower light source 23c) provided in the lighting unit 23 are annular light sources (annular lighting sources), but can be divided into a plurality of parts (for example, divided into four parts). In the case of this structure, it is expected that the control unit 30 can control the lighting and extinguishing of each part (can perform split lighting). According to this structure, in each light source (upper light source 23a, middle light source 23b, and lower light source 23c), by lighting all parts, the object to be inspected 12 can be illuminated in all directions from 0° to 360°, and by lighting a local part (extinguishing the remaining part), the object to be inspected 12 can be illuminated from a specific direction. In this case, it can be configured so that all of the upper light source 23a, the middle light source 23b, and the lower light source 23c can be split and lit, or it can be configured so that any one light source or any two light sources can be split and lit.

[0060] As described above, the inspection device 10 involved in this embodiment reflects the illumination light from the light sources 23a~23c through the dome-shaped reflection plate 230 and irradiates it onto the inspected object 12. Compared with the structure in which the light from the light source is directly irradiated onto the inspected object 12 as in the past, the inspection equipment (the second camera unit 22, the projection unit 24) installed in the inclined direction can be brought closer to the inspected object 12 as the imaging object, thereby improving the resolution of the camera and the high reproducibility based on the refinement of the stripes, resulting in improved inspection accuracy.

[0061] Furthermore, by using the dome-shaped reflection plate 230 , it is not necessary to use a diffusion plate for diffusing the illumination light from the light sources 23 a to 23 c , and thus it is possible to reduce the loss of light amount.

[0062] In addition, Figure 3 In FIG. 1 , the double-dashed line indicates the optical axis (imaging axis) of the first imaging unit 21, the second imaging unit 22, and the projection unit 24. In addition, the dotted line indicates the light beams of illumination light emitted from the upper light source 23a, the middle light source 23b, and the lower light source 23c, respectively, and reflected from the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c, respectively, to irradiate the inspection object 12. Figure 3 As clearly stated, regarding the inner peripheral surfaces 232a to 232c of the upper reflector 230a, the middle reflector 230b, and the lower reflector 230c, since the surfaces of the protrusions 231a and 231b on the side of the object to be inspected 12 are also reflective surfaces, there is almost no gap between the light beam LFa of the illumination light irradiated from the upper reflector 230a to the object to be inspected 12 and the light beam LFb of the illumination light irradiated from the middle reflector 230b to the object to be inspected 12, and there is almost no gap between the light beam LFb of the illumination light irradiated from the middle reflector 230b to the object to be inspected 12 and the light beam LFc of the illumination light irradiated from the lower reflector 230c to the object to be inspected 12. Therefore, the area on the object to be inspected 12 where the illumination light is not irradiated (the above-mentioned "blind area") can be eliminated, and the measurement accuracy based on the image data of the object to be inspected 12 captured in this state can be improved.

[0063] In addition, the illumination unit 23 of the inspection device 10 according to the present embodiment does not directly irradiate the illumination light emitted from the light sources 23a to 23c onto the inspection object 12 as described above, but reflects the illumination light on the reflector 230 and irradiates the inspection object 12. If the inspection object 12 is photographed in a state where the illumination light from the light sources 23a to 23c is directly irradiated onto the inspection object 12, the deviation in brightness of the image data obtained by the photographing becomes large, but by irradiating the illumination light from the light sources 23a to 23c by reflecting it once on the reflector 230, the deviation in brightness in the image data can be suppressed, and the measurement accuracy based on the image data can be improved.

[0064] In addition, as described above, the inspection devices such as the first camera unit 21, the second camera unit 22, and the projection unit 24 are arranged so that their optical axes pass through the opening 233 and the through holes 237 and 238 formed in the reflector 230. Since the reflector 230 can be made into a thin structure, the opening 233 and the through holes 237 and 238 can be reduced, and as a result, the reflection surface in the inner peripheral surface of the reflector 230 can be expanded, and the area (blind spot) on the inspected object 12 that is not irradiated with the illumination light can be reduced.

[0065] In addition, since the field of view or irradiation field of the inspection device becomes wider as it moves away from the inspection device, it is desirable to configure the inner peripheral surface of the through holes 237 and 238 in the reflector 230 to have a tapered shape along the field of view or irradiation field. Figure 4 As shown in (a) of FIG. 1 , the inner peripheral surface of the through holes 237 and 238 may be set to a tapered shape along the optical axis of the inspection device 22 and 24 so that the inner peripheral surface is substantially parallel to the optical axis. Alternatively, Figure 4 As shown in (b), the through holes 237 and 238 are tapered so as to widen from the inspection device 22 and 24 side to the inspection object 12 side. By setting the through holes 237 and 238 in such a tapered shape, the through holes 237 and 238 can be reduced, and the area (blind spot) on the inspection object 12 that is not irradiated with illumination light can be reduced.

[0066] In addition, in the above description, the following situation is described: the light source of the lighting unit 23 is composed of an upper light source 23a, a middle light source 23b and a lower light source 23c, and each light source is respectively arranged in a divided part of the reflecting plate 230, namely, an upper reflecting plate 230a, a middle reflecting plate 230b and a lower reflecting plate 230c, but the light source and the divided part of the reflecting plate are not limited to 3 groups, and can also be composed of 2 or 4 or more groups.

[0067] Finally, a method for processing image data obtained by using the illumination unit 23 is described. As described above, in the inspection device 10 according to the present embodiment, the light sources (upper light source 23a, middle light source 23b, and lower light source 23c) constituting the illumination unit 23 are as follows: Figure 5 As shown in (a) of FIG. 1 , the light sources 23a, 23b, and 23c are arranged in a manner that is inclined relative to the optical axis (imaging axis) L of the first imaging unit 21 and has different projection angles relative to the reference plane of the object to be inspected 12 (the inspection plane of the object to be inspected 12, i.e., the plane that is substantially parallel to the installation plane of the inspection device 10). Specifically, the upper light source 23a, the middle light source 23b, and the lower light source 23c are projected in a manner that the projection angles approach the horizontal direction in this order.

[0068] The intensity of light emitted from each light source 23a to 23c of the illumination unit 23, reflected from each divided portion 230a to 230c of the reflection plate, and projected onto the inspected object 12 and reflected from the inspected object 12, except for the light reflected from the inspected object 12 and directly incident on the first camera unit 21, varies depending on the state of the measured object. However, for example, in the case of a structure with a reflectivity close to 100%, the above intensity is ideally zero, that is, the angle (inclined state) of the inspection surface of the inspected object 12 relative to the reference plane, the intensity of the reflected light generated by the light source directly incident on the first camera unit 21 becomes larger, and the intensity of the reflected light generated by the other light sources is 0. For example, a portion of the inspection surface of the inspected object 12 is formed with a plurality of light sources 23a to 23c. Figure 5 In the case of the solder having a cross section shown in (b), the intensity of reflected light of the illumination light generated by each light source 23a to 23c of the illumination unit 23 detected by the imaging element of the first imaging unit 21 varies according to the angle of the surface of the solder relative to the reference plane.

[0069] Therefore, in Figure 5 In the case of (a), regarding the intensity of light detected by the first imaging unit 21, the inclined surface close to the reference surface makes the light from the upper light source 23a stronger, and as the inclination of the inclined surface relative to the reference surface increases, the intensity of the detected light changes in the order of the middle light source 23b and the lower light source 23c. Therefore, in the image data captured by the first imaging unit 21, by determining which light source has the strongest intensity of light, the angle of the inclined surface at the position where the light is reflected on the subject 12 can be estimated.

[0070] The angle of the inclined surface of the object to be inspected (for example, the angle of the solder surface) estimated from the image data obtained by the first camera unit 21 through the illumination by the illumination unit 23 (light source 23a to 23c and the division part 230a to 230c of the reflector 230) as described above can be determined by the central angle of the illumination and the illumination range. However, it is necessary to also consider the change of the illumination angle caused by the position in the field of view (FOV) of the first camera unit 21, the setting value of the first camera unit 21, etc.

[0071] In addition, the relationship between the angle of the inclined surface of the object to be inspected 12 and each light source 23a to 23c of the lighting unit 23 is an example and is not limited to this structure. For example, if the light sources are set to 4 or more (the combination of the light source and the dividing part of the reflector is set to 4 or more), the illumination range of each light source becomes narrower, and the more light sources are added, the greater the resolution when estimating the angle of the inclined surface of the object to be inspected 12 (for example, the angle of the solder surface) based on the image data obtained by shooting. In addition, when the object to be inspected 12 is an inspection object with a high reflectivity such as a metal ball, it is impossible to measure within the range of 0° to 90°.

[0072] According to the above, the intensity of each pixel of the image data obtained by lighting each light source 23a to 23c of the illumination unit 23 and photographing by the first imaging unit 21 becomes large when the angle of the inclined surface is consistent with the angle of the inclined surface, and becomes a value close to 0 when the angle of the inclined surface is inconsistent with the angle of the inclined surface. In addition, the same is true for the image data photographed by the second imaging unit 22 whose optical axis is arranged at an angle different from the optical axis of the first imaging unit 21, and an angle range different from the angle range of the inclined surface that can be estimated from the image data photographed by the first imaging unit 21 can be estimated. Therefore, the inspection device 10 according to the present embodiment is configured to estimate the angle of the inclined surface of the inspection object 12 (for example, the angle of the solder) for each pixel based on the intensity of the light, based on the image data obtained by the first imaging unit 21 and the second imaging unit 22, by reflecting the light from each light source 23a to 23c of the illumination unit 23 on the reflector 230 (dividing parts 230a to 230c) and projecting it onto the inspection object 12.

[0073] Alternatively, the light sources 23a to 23c may be sequentially lit and the first and second imaging units 21 and 22 may be used to capture images of the subject 12, or the first and second imaging units 21 and 22 may be configured with cameras capable of acquiring color image data, and the light sources 23a to 23c may be simultaneously lit in different colors to capture images of the subject 12 at once. In this case, image data corresponding to the respective light sources 23a to 23c may be acquired by acquiring image data of the R (red) component, image data of the G (green) component, and image data of the B (blue) component from one color image data.

[0074] The inspection object for estimating the angle of the inclined surface of the inspection object 12 based on the image data captured by the first and second imaging units 21 and 22 is not limited to the solder surface, but can also be applied to the shape of the tip of an IC lead or the shape of a chip electrode.

[0075] Description of Reference Numerals

[0076] 10: Inspection device; 12: Object to be inspected (object to be imaged); 20: Image pickup unit (image pickup section); 21: First image pickup section (main image pickup section); 22: Second image pickup section (inspection equipment, tilt image pickup section); 23: Illumination section; 23a to 23c: Light source; 24: Projection section (inspection equipment); 30: Control unit; 230: Reflection plate; 230a to 230c: Splitting section; 233, 234, 235, 236: Openings; 237, 238: Through holes.

Claims

1. An inspection device comprising: A main camera unit, which is used to shoot the object from a vertical direction; A plurality of reflectors, each of which is dome-shaped and disposed between the main imaging unit and the imaging object, and each of which has an opening on a side close to the main imaging unit and a side close to the imaging object; A plurality of light sources, wherein the plurality of light sources are in a ring shape and illuminate each of the reflective plates; as well as an inspection device, which is located outside the reflector and can photograph or irradiate the imaging object with light, The optical axis of the inspection device is configured to pass through a through hole provided in the reflection plate.

2. The inspection device according to claim 1, wherein: The plurality of reflecting plates are connected in a vertical direction so as to connect the openings. The radius of the opening of the reflector on the main imaging unit side, which is on the imaging object side, and the radius of the opening of the reflector on the imaging object side, which is on the main imaging unit side, are the same size.

3. The inspection device according to claim 1 or 2, wherein: Regarding the plurality of light sources, it is possible to control the lighting timing and the light emission color for each of the light sources.

4. The inspection device according to claim 1 or 2, wherein: The inspection device includes at least one of an oblique imaging unit for imaging the imaging object from an oblique direction, a projection unit capable of projecting pattern fringes for three-dimensional measurement, and a specific wavelength irradiation unit irradiating illumination light of a specific wavelength.

5. The inspection device according to claim 1 or 2, wherein: The inspection devices are arranged in a ring shape on the reflection plate at intervals from each other.

6. The inspection device according to claim 1 or 2, wherein: The inspection device is configured such that the closer the reflector is arranged to the imaging object, the larger the angle formed by the imaging axis of the main imaging unit and the optical axis of the inspection device.

7. The inspection device according to claim 1 or 2, wherein: The through hole has a tapered shape in the reflection plate.

8. The inspection device according to claim 1 or 2, wherein: The through holes are arranged in a ring shape in the reflector at intervals from each other.

9. The inspection device according to claim 1 or 2, wherein: At least one of the plurality of light sources may be divided into a plurality of parts, and lighting and extinguishing may be controlled for each of the parts.

Images