JP2021086121A - Image capture device and surface inspection device - Google Patents

Abstract

To provide an image capture device capable of capturing a high-quality image suitable for inspection of a surface, and a surface inspection device.SOLUTION: An image capture device 10 comprises a camera 30 to capture an image of a subject, and an illumination device 40 to illuminate the subject with illumination light. The camera 30 comprises an optical system in which an image acquisition plane is a plane of sharp focus, and acquires image data by obliquely capturing an image of the subject being in an image capture range such that the subject is within a depth of field. The illumination device 40 has a variable position of a light source part and can change how to illuminate the subject with the illumination light.SELECTED DRAWING: Figure 1

Description

The present invention relates to an imaging device and a surface inspection device.

A device is known in which the surface of a work is imaged with a camera and the surface of the work is inspected using the captured image.

Patent Document 1 proposes a method of obliquely imaging a work as a method of capturing an image for inspection. When the work is imaged at an angle, the image is distorted (projection distortion). In Patent Document 1, distortion is eliminated by performing fluoroscopic transformation of the captured image.

Further, when the work is imaged at an angle, there is a difference in resolution in the image. Patent Document 2 proposes a method in which the imaging regions of each camera are overlapped and a workpiece is imaged obliquely by a plurality of cameras.

Japanese Unexamined Patent Publication No. 2014-167456 Japanese Unexamined Patent Publication No. 2018-146442

One embodiment according to the technique of the present disclosure provides an imaging device and a surface inspection device capable of capturing a high quality image suitable for surface inspection.

(1) An imaging unit having an imaging optical system in which the image acquisition surface is the in-focus surface, the subject within the imaging range is contained within the depth of field, and the subject is imaged at an angle to acquire image data, and the subject is irradiated. An imaging device including an illumination unit in which the direction of the main light beam of the illumination light and / or the position of the light source unit of the illumination light is variable.

(2) An image processing unit that performs image processing on the image data is further provided, and the image processing unit emphasizes the difference in the image data caused by changing the direction of the main ray of the illumination light and / or the position of the light source unit of the illumination light. The imaging device of (1), which performs the process of performing the processing.

(3) The illumination unit includes a light source unit and a moving mechanism of the light source unit, and the moving mechanism moves the light source unit to change the position of the light source unit of the illumination light. apparatus.

(4) The image pickup apparatus according to (3), wherein the illumination unit further includes a swing mechanism of the light source unit, and the swing mechanism changes the direction of the light source unit to change the direction of the main light beam of the illumination light.

(5) The illumination unit includes a light source unit and a swing mechanism of the light source unit, and the direction of the light source unit is changed by the swing mechanism to change the direction of the main light beam of the illumination light, (1) or (2). ) Imaging device.

(6) The image pickup apparatus according to (1) or (2), wherein the illumination unit includes a plurality of light source units, changes the light source unit to be turned on, and changes the position of the light source unit of the illumination light.

(7) The image pickup apparatus according to (6), wherein the illumination unit further includes a swing mechanism of the light source unit, and the swing mechanism changes the direction of the light source unit to change the direction of the main light beam of the illumination light.

(8) The image pickup apparatus according to (6) or (7), wherein a plurality of light source units are arranged in a matrix.

(9) The imaging device according to any one of (6) to (8), in which a plurality of light source units are arranged in an arc shape.

(10) An imaging device according to any one of (1) to (9), comprising a plurality of imaging units in which imaging ranges are set to overlap.

(11) An imaging device according to any one of (1) to (10), further comprising a holding portion for holding a subject and a rotating mechanism for the holding portion.

(12) An imaging unit having an imaging optical system in which the image acquisition surface is the in-focus surface, the subject within the imaging range is contained within the depth of field, and the subject is imaged at an angle to acquire image data, and the subject is illuminated. An imaging device including an illumination unit that irradiates light, a holding unit that holds a subject, and a driving unit that moves or tilts the imaging unit and the holding unit in an interlocking manner.

(13) An image processing unit that performs image processing on the image data is further provided, and the image processing unit emphasizes the difference in the image data caused by changing the direction of the main ray of the illumination light and / or the position of the light source unit of the illumination light. (12) The image pickup apparatus for performing the processing.

(14) The imaging optical system of the imaging unit includes one mirror having positive power and an optical system composed of a plurality of lenses having positive power in order from the object side, and the mirror and the optical system The imaging device according to any one of (1) to (13), which forms an intermediate image between the two.

(15) The image pickup apparatus according to (14), wherein the mirror and the optical system have a common optical axis and have a rotationally symmetric shape with the optical axis as the rotation axis.

(16) A surface inspection device including any one of the image pickup devices (1) to (15) and an inspection section for inspecting the surface of a work using image data acquired by the image pickup section.

The figure which shows the schematic structure of the surface inspection apparatus. The figure which shows the schematic structure of the image pickup apparatus Cross-sectional view showing the schematic configuration of the camera Cross-sectional view showing the configuration of the imaging optical system Cross-sectional view showing the configuration of the imaging optical system Floor plan of the lighting device Block diagram showing an example of the hardware configuration of the inspection device body Block diagram of the functions realized by the inspection device body The figure which shows an example of the image obtained by changing the way of illuminating light Flowchart showing the procedure of the process to determine the optimum lighting position Side view of the lighting device Floor plan of the lighting device Side view showing a modified example of the lighting device Floor plan of the lighting device Side view of the lighting device Floor plan of the lighting device Side view of the lighting device The figure which shows the schematic structure of the surface inspection apparatus. The figure which shows the schematic structure of the surface inspection apparatus. Perspective view showing the arrangement of cameras The figure which shows the modification of the surface inspection apparatus Schematic diagram showing the configuration of an imaging device The figure which shows an example of the structure of the image pickup apparatus when inspecting a strip-shaped workpiece

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
Minute irregularities such as minute grooves, scratches, bubbles, and unevenness of the film existing on a flat surface or a gentle curved surface are imaged by a normal imaging method (a method of photographing the subject directly with a normal camera). But it doesn't show up. Or, even if it is captured, it is only faintly captured.

By imaging from an angle, it is possible to easily find these minute irregularities. It can be seen that this method is intuitively useful from the fact that when a human confirms a minute unevenness in a plane, he / she takes an action of looking at it from an angle with his / her eyes close to each other.

However, when an image is taken from an angle with a normal camera, the image is distorted (projection distortion) or the resolution is different in the image.

The surface inspection apparatus of the present embodiment captures a high-quality image suitable for inspection by using a special camera having a wide range of focus even if the image is taken from an angle. Further, the surface inspection device of the present embodiment creates an optimum lighting environment and images by using a lighting device (a lighting device in which the lighting method is variable) that can change the lighting method. ..

In the following, a case of inspecting the surface of a sheet-shaped work will be described as an example.

[Configuration of surface inspection equipment]
FIG. 1 is a diagram showing a schematic configuration of a surface inspection device according to the present embodiment.

As shown in the figure, the surface inspection device 1 of the present embodiment controls the image pickup device 10 for capturing the surface of the work W and the image pickup device 10, and uses the image captured by the image pickup device 10. The inspection device main body 100 for inspecting the surface of the work W is provided. The inspection device main body 100 inspects the presence or absence of defects on the surface of the work, particularly minute irregularities such as minute grooves, scratches, bubbles, and unevenness of the film.

[Imaging device]
FIG. 2 is a diagram showing a schematic configuration of an imaging device.

The image pickup apparatus 10 includes a stage 20 on which the work W is placed, a camera 30 that images the work W mounted on the stage 20, and an illumination device 40 that irradiates the work W mounted on the stage 20 with illumination light. Be prepared.

[stage]
The stage 20 has a flat work mounting surface 20a. The work W is placed on the work mounting surface 20a. In this embodiment, the stage 20 is installed horizontally. Therefore, the work W is held horizontally. It is preferable that the stage 20 is provided with a mechanism for sucking and holding the work W as needed. The stage 20 is an example of a holding portion.

The stage 20 is installed so that the work mounting surface 20a is within the imaging range of the camera 30. Therefore, the entire (entire surface) of the work W mounted on the work mounting surface 20a can be imaged.

[camera]
The camera 30 is a so-called perspective camera, and a subject (work W) within the imaging range is captured within the depth of field and imaged obliquely, and the image data is acquired. This type of camera can be realized by setting the imaging range in a region that does not include the optical axis of the imaging optical system. That is, by setting the imaging range in a region that does not include the optical axis of the imaging optical system, all the subjects (main subjects) within the imaging range are contained within the depth of field, and the image facing the subject is viewed from an angle. Can be imaged. The camera 30 of the present embodiment takes an image of the work W horizontally placed on the work mounting surface 20a from diagonally above the work W. The camera 30 is an example of an imaging unit. The surface of the work W is the main subject.

FIG. 3 is a cross-sectional view showing a schematic configuration of the camera.

As shown in the figure, the camera 30 includes an imaging optical system 32 and an image sensor 33 inside the housing 31. The housing 31 has a prismatic shape and is configured to be self-supporting by being placed on a horizontal plane. The housing 31 has an imaging window 31a on the front surface. The camera 30 faces the subject (work W) diagonally downward from the image pickup window 31a and takes an image.

The imaging optical system 32 includes one mirror M1 having a positive power and an optical system RO composed of a plurality of lenses and having a positive power in order from the object side.

4 and 5 are cross-sectional views showing the configuration of the imaging optical system. In FIGS. 4 and 5, the luminous flux A in the vicinity of the optical axis Z and the luminous flux B having the maximum angle of view are also entered as the luminous flux. Further, in FIG. 4, the mirror M1 side is shown as the object side and the image plane Sim side is shown as the image side along the optical axis Z. Further, FIG. 5 is an enlarged view of the imaging optical system portion in FIG. The intermediate image I and the aperture stop St shown in FIGS. 4 and 5 do not show the shape but the position on the optical axis.

As shown in the figure, the imaging optical system 32 of the camera 30 of the present embodiment is composed of one mirror M1 having a positive power and a plurality of lenses in order from the object side and having a positive power. It has an RO, and an intermediate image I is formed between the mirror M1 and the optical system RO. By forming the intermediate image I in the imaging optical system in this way, it is possible to suppress the expansion of the luminous flux in the imaging optical system. This makes it possible to construct a compact and wide-angle imaging optical system.

As an example, the optical system RO of the present embodiment is a front group composed of four lenses L1 to L4 (first lens L1, second lens L2, third lens L3, and fourth lens L4) in order from the object side. It has a GF, an aperture aperture St, and a rear group GR composed of three lenses L5 to L7 (fifth lens L5, sixth lens L6, and seventh lens L7).

The mirror M1 and the optical system RO of the present embodiment have a common optical axis Z and have a rotationally symmetric shape with the optical axis Z as the rotation axis. With such a configuration, the design of the imaging optical system 32 becomes easy. Further, the workability and assembling property of the optical elements constituting the imaging optical system 32 can be improved. As a result, the performance can be improved while suppressing the cost of the imaging optical system. In the imaging optical system 32 of the present embodiment, the regions of the mirror M1 and the optical system RO that are not used for imaging are partially cut off. The shape in which the region not used for imaging is partially cut is also included in the rotationally symmetric shape with the optical axis Z as the rotation axis.

The mirror M1 of the present embodiment has an aspherical shape. As described above, by forming the mirror M1 which is arranged on the object side most and has a large effective diameter into an aspherical shape, it is advantageous for correcting curvature of field, coma, astigmatism, and distortion.

In the optical system RO of the present embodiment, the first lens L1 (the lens on the most object side of the optical system RO) is composed of a positive lens having a concave surface facing the object side. By making the object side of the first lens L1 concave in this way, the angle of view can be widened while suppressing the diameter of the first lens L1. Further, by using the first lens L1 as a positive lens, the luminous flux incident from the mirror M1 converges and is emitted. Therefore, the diameter of the next second lens L2 can be reduced, and the overall length of the optical system RO can be shortened. Therefore, the imaging optical system 32 can be miniaturized.

As described above, the imaging optical system 32 of the present embodiment can form a compact and wide-angle imaging optical system. Therefore, the camera 30 provided with the imaging optical system 32 of the present embodiment can also be configured as a compact camera capable of capturing a wide range.

In the imaging optical system 32 having the above configuration, the distance on the optical axis Z from the reflecting surface of the mirror M1 to the imaging surface Sim is TTL, and the optical axis Z from the reflecting surface of the mirror M1 to the object surface Obj (image acquisition surface). When the upper distance is ZOB, the distance on the optical axis Z from the object side surface of the first lens L1 to the image plane Sim is LL0, and the maximum image height is Ymax, the following conditional equations (1) and (2) ) Is preferably satisfied. The maximum image height Ymax means the distance between the image point farthest from the optical axis Z and the optical axis Z.

0.8 <TTL / ZOB <1 ... (1)
6 <LL0 / Ymax <15 ... (2)
For example, in order to install the camera 30 on a surface (object surface Obj) having the same height as the work mounting surface 20a of the stage 20, a mirror M1 that bends the luminous flux of the incident light is required. By not making it less than the lower limit of the conditional expression (1), the total length of the imaging optical system 32 is not shortened too much, which is advantageous for correcting aberrations. By not exceeding the upper limit of the conditional expression (1), it is advantageous for the miniaturization of the device.

By not making it less than the lower limit of the conditional expression (2), the total length of the optical system RO is not too short with respect to the maximum image height Ymax, which is advantageous for correcting aberrations. It is advantageous for miniaturization of the device by not exceeding the upper limit of the conditional expression (2).
If the conditional expressions (1) and (2) are satisfied and at least one of the following conditional expressions (1-1) and (2-1) is satisfied, the characteristics will be better. Can be done.

0.85 <TTL / ZOB <0.95 ... (1-1)
7 <LL0 / Ymax <13 ... (2-1)
Further, when the focal length of the first lens is fL1 and the focal length of the optical system RO is fL0, it is preferable that the following conditional expression (3) is satisfied.

3 <fL1 / fL0 <50 ... (3)
In order to reduce the size of the optical system RO while increasing the effective diameter of the first lens L1, the first lens L1 needs an appropriate positive power. However, it is necessary that the positive power of the first lens L1 is not too large because the larger the effective diameter of the second lens L2 is, the more advantageous it is for aberration correction. By making sure that the value does not fall below the lower limit of the conditional expression (3), the positive power of the first lens L1 can be prevented from becoming too large. An appropriate positive power can be secured for the first lens L1 by not exceeding the upper limit of the following conditional expression (3).

If the following conditional expression (3-1) is satisfied, better characteristics can be obtained.

4 <fL1 / fL0 <25 ... (3-1)
Further, the optical system RO has a configuration having a front group GF having a positive power, an aperture stop St, and a rear group GR having a positive power in order from the object side, and the front group GF is an object. It is preferable to have a configuration having a first lens L1, a second lens L2 having a negative power, and a third lens L3 having a positive power in order from the side. In this way, by making the power of the second lens L2 negative, it is possible to prevent the light rays from suddenly converging, and further, the first lens L1, the second lens L2, and the third lens L3 having a relatively large effective diameter. By configuring the power arrangement of the three lenses as positive and negative positive configurations and dispersing the positive and negative actions, it is advantageous for correcting coma aberration and curvature of field.

Further, it is preferable that the rear group GR is provided with the junction lens C1 having the following configuration on the image side most. That is, a bonded lens composed of a positive lens and a negative lens and having positive power as a whole, in which the Abbe number of the positive lens is 50 or more and the Abbe number of the negative lens is 40 or less. is there. In the imaging optical system 32 of the present embodiment, the junction lens C1 is configured by the sixth lens L6 which is a positive lens and the seventh lens L7 which is a negative lens. As described above, by arranging the junction lens C1 having the above configuration on the image side of the aperture diaphragm St and at a position where the height of the off-axis main light ray is high, it is advantageous for correcting the chromatic aberration of magnification. Further, when the front group GF is provided with a positive lens and a negative lens, the rear group GR on the image side of the aperture stop St is also provided with the positive lens and the negative lens, which is advantageous for correcting curvature of field and distortion. Become.

The Abbe numbers of the positive and negative lenses constituting the bonded lens C1 satisfy the above conditions, and the Abbe numbers of the positive lenses constituting the bonded lens C1 are 55 or more, and the negative numbers constituting the bonded lens C1. If at least one of the Abbe numbers of the lens is 30 or less is satisfied, better characteristics can be obtained.

Further, in the optical system RO, it is preferable that the first lens L1 is composed of an aspherical lens, while the lenses other than the first lens L1 are composed of a spherical lens. In this way, aberrations are effectively corrected by forming the first lens L1, which is located on the most object side of the optical system RO, has a large effective diameter, and has a small overlap of light fluxes with respect to different image heights, into an aspherical shape. it can. Further, by using all the remaining lenses of the optical system RO as spherical lenses, it is advantageous to improve the workability and the assembling property of the optical elements constituting the imaging optical system. As a result, it is advantageous in improving the performance while suppressing the cost of the imaging optical system 32.

The image pickup device 33 is arranged on the imaging surface of the imaging optical system 32. As described above, in the camera 30 of the present embodiment, the imaging range is set in a region that does not include the optical axis of the imaging optical system. Therefore, the image pickup device 33 is arranged in the image circle of the imaging optical system 32 in a region not including the optical axis Z of the imaging optical system 32. That is, it is arranged so that the optical axis Z of the imaging optical system 32 is not included in the light receiving region. As a result, the imaging range is set in a region that does not include the optical axis of the imaging optical system.

It is also possible to arrange the image pickup device 33 on the optical axis of the imaging optical system 32, cut out a part of the image obtained by the imaging, and acquire the image data of the necessary region.

A known area image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) can be used as the image sensor 33.

According to the camera 30 having the above configuration, the image acquisition surface of the imaging optical system 32 is a focal plane, and all the subjects (work W) within the imaging range can be captured within the depth of field and imaged from an oblique angle. In addition, an image facing the subject can be captured at an angle.

In the image pickup apparatus 10 of the present embodiment, the work mounting surface 20a of the stage 20 is set as the image acquisition surface. Therefore, the work mounting surface 20a is set as the focusing surface. Further, in the imaging device 10 of the present embodiment, the work mounting surface 20a of the stage 20 is set within the imaging range. Therefore, by placing the sheet-shaped work W on the work mounting surface 20a and taking an image, the entire work W can be captured within the depth of field. The work mounting surface 20a may be set at least within the imaging range of the camera 30. In the present embodiment, the imaging range of the camera 30 is set in substantially the same range as the work mounting surface 20a.

[Lighting device]
FIG. 6 is a plan view of the lighting device. As shown in FIG. 6, the lighting device 40 includes a light source unit 42 and a moving mechanism 44 of the light source unit 42. The lighting device 40 is an example of a lighting unit.

The light source unit 42 irradiates the work W with illumination light. The light source unit 42 is an example of a light source unit. The light source unit 42 is installed above the stage 20 and irradiates the work W with illumination light from above. In the light source unit 42, the direction of the main light beam is set perpendicular to the work mounting surface 20a, and the illumination light is irradiated perpendicularly to the work W.

The light source unit 42 has a line-shaped light source 43. In the present embodiment, a plurality of light emitting elements 43a (for example, a light emitting diode (LED) or the like) are arranged in a line to form a line-shaped light source 43. As the light source unit 42, a reflector, a lens, a diffuser, and the like are used as needed, and the irradiation angle, light distribution characteristics, and the like are adjusted.

In the light source unit 42, the line-shaped light source 43 is arranged parallel to the work mounting surface 20a. Further, in the light source unit 42, a line-shaped light source 43 is arranged along the x-axis. The x-axis is an axis parallel to the work mounting surface 20a.

The moving mechanism 44 moves the light source unit 42 horizontally along the work mounting surface 20a. In this embodiment, as shown in FIG. 2, the light source unit 42 is moved along the y-axis. The y-axis is an axis parallel to the work mounting surface 20a and orthogonal to the x-axis.

The moving mechanism 44 has a guide unit that guides the movement of the light source unit 42, and a slide drive unit that moves the light source unit 42.

The guide portion has a guide rail 46a. The guide rail 46a is arranged along the y-axis. The light source unit 42 is slidably supported by the guide rail 46a via the slider 46b.

The slide drive unit is mainly composed of a feed screw 48a and a motor 48b. The lead screw 48a is arranged along the y-axis, and both ends thereof are rotatably supported by bearings. The motor 48b is connected to the feed screw 48a and rotationally drives the feed screw 48a. The light source unit 42 is connected to a nut 48c provided on the feed screw 48a. As a result, when the feed screw 48a is rotated by the motor 48b, the light source unit 42 slides along the guide rail 46a. That is, it slides along the y-axis.

According to the lighting device 40 having the above configuration, when the light source unit 42 is moved by the moving mechanism 44, the relative position of the light source unit 42 with respect to the work W changes. As a result, the way the illumination light hits the work W is switched.

[Inspection device body]
FIG. 7 is a block diagram showing an example of the hardware configuration of the inspection device main body.

As shown in the figure, the inspection device main body 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an HDD (Hard Disk Drive) 104, and an operation unit (for example, Keyboard, mouse, etc.) 105, display unit (for example, liquid crystal display (LCD), organic electro-Luminescence display (OELD), etc.) 106, input / output interface (interface; I / F) 107 It is composed of a computer provided with a communication unit 108 and the like. The camera 30 and the lighting device 40 constituting the image pickup device 10 are connected to the inspection device main body 100 via the input / output interface 107.

FIG. 8 is a block diagram of the functions realized by the inspection device main body.

As shown in the figure, the inspection device main body 100 includes a camera control unit 111, a lighting control unit 112, an image input unit 113, an image processing unit 114, a lighting condition determination unit 115, an inspection unit 116, a display control unit 117, and recording control. The functions of the unit 118 and the communication control unit 119 are realized. These functions are realized by the CPU 101, which is a processor, executing a predetermined program. The program is stored in, for example, the ROM 103 or the HDD 104.

The camera control unit 111 controls the camera 30 to control the image pickup by the camera 30. Imaging is performed in conjunction with a change in how the illumination light is applied. Image data is output from the camera 30 by imaging.

The illumination control unit 112 controls the illumination device 40 to control the emission of illumination light. The control of light emission also includes control of how the illumination light is applied. In the present embodiment, the movement of the light source unit 42 is controlled to control how the illumination light is applied. That is, the position of the light source unit 42 with respect to the work W is controlled to control how the illumination light is applied.

The image input unit 113 inputs image data output from the camera 30. The image data is input to the inspection device main body 100 via the input / output interface 107.

The image processing unit 114 performs image processing on the input image data. The image processing unit 114 performs processing for emphasizing the difference in image data caused by changing the method of applying the illumination light. In the present embodiment, as this process, a process of enhancing the contrast of the image is performed. By emphasizing the contrast, the shadow of the defect can be emphasized and the defect can be easily found. A known method may be used for the process of enhancing the contrast of the image. Therefore, the details thereof will be omitted here. For example, a method of enhancing the contrast of an image by filtering is adopted.

The illumination condition determination unit 115 determines the optimum illumination condition based on the image data obtained by shooting. In the present embodiment, the optimum illumination position (position of the light source unit 42) is determined. The illumination condition determination unit 115 determines the optimum illumination position based on a plurality of image data captured by changing the method of irradiating the illumination light. Specifically, the position of the light source unit 42 in which the contrast of the shadow of the defect appears most clearly is specified from a plurality of image data captured by changing the method of applying the illumination light.

FIG. 9 is a diagram showing an example of an image obtained by taking an image by changing the method of applying illumination light. FIGS. (A) to (D) show captured images WI1 to WI4 of the work W obtained at different illumination positions. Further, in the figure, reference numerals SI1 to SI3 indicate defects (fine irregularities) on the work surface. More precisely, it shows the shadow of defects that appear due to lighting. As shown in the figure, the appearance (contrast) of the shadow of the defect changes as the illumination position changes.

The illumination condition determination unit 115 identifies the image data in which the contrast of the shadow of the defect appears most clearly, and determines the position of the light source unit 42 when the image data is imaged as the optimum illumination position. The illumination condition determination unit 115 determines the optimum illumination condition based on the image data after the image processing by the image processing unit 114. This makes it easier to identify the optimum lighting conditions.

The inspection unit 116 inspects the presence or absence of defects using the image data after image processing. In the present embodiment, the presence or absence of minute irregularities such as minute grooves, scratches, air bubbles, and uneven film is inspected. Any algorithm, including a known method, may be used to detect these minute irregularities (defects). Therefore, the details thereof will be omitted here. As an example, a method of recognizing (detecting) minute irregularities or the like can be adopted by using an image recognition model generated by machine learning, deep learning, or the like. The inspection unit 116 identifies the position and size of the defect and detects the defect.

The display control unit 117 controls the display of the inspection result. The inspection result is displayed on the display unit 106 in a predetermined format.

The recording control unit 118 controls the recording of the inspection result. The inspection result is recorded in the HDD 104 in a predetermined format.

The communication control unit 119 controls the transmission of the inspection result to the external device. The inspection result is transmitted to an external device via the communication unit 108. The form of communication is not particularly limited.

[Action of surface inspection device]
[Determining the optimum lighting position]
First, the optimum lighting position is determined.

FIG. 10 is a flowchart showing the procedure of the process of determining the optimum illumination position.

First, the work for determining the lighting position is set on the stage 20 (step S11). This work is a work having known defects (fine irregularities) on the surface. The work is set on the stage 20 by placing it on the work mounting surface 20a. By placing the work on the work mounting surface 20a, the work is set within the imaging range of the camera 30.

When the work setting is completed, the light source unit 42 is then turned on and the illumination light is turned on (step S12). As a premise, it is assumed that the light source unit 42 is located at a predetermined start point position at this point.

Next, the camera 30 is driven and imaging is performed (step S13). The image data obtained by imaging is output to the inspection device main body 100. The image data is taken into the inspection device main body 100 and stored in the RAM 102.

Next, the moving mechanism 44 of the light source unit 42 is driven, and the light source unit 42 moves by one step (step S14). This moving force (moving distance for one step) is a predetermined distance.

Next, it is determined whether or not the light source unit 42 has reached the terminal position (step S15). The end position is set within the movable range of the light source unit 42.

If it is determined that the light source unit 42 has not reached the terminal position, the process returns to step S13, and imaging is performed again. The imaging is repeated until the light source unit 42 reaches the terminal position. In this way, while moving the light source unit 42, imaging is performed a plurality of times. As a result, the work W is imaged a plurality of times while the lighting is changed.

When it is determined that the light source unit 42 has reached the terminal position, the light source unit 42 is turned off and the illumination light is turned off (step S16).

Imaging of the work W is completed in the above series of steps. Next, a process of setting the light source unit 42 at an optimum position is performed using the image data obtained by imaging.

First, image processing is performed on a plurality of image data obtained by imaging (step S17). The image processing is a process of emphasizing the difference in the image data caused by changing the method of applying the illumination light. Specifically, a process of enhancing the contrast is performed.

Next, the optimum illumination position is determined based on the plurality of image-processed image data (step S18). Specifically, the image data in which the contrast of the shadow of the defect appears most clearly is specified, and the position of the light source unit 42 when the image data is imaged is determined as the optimum illumination position.

Next, the moving mechanism 44 of the light source unit 42 is driven, and the light source unit 42 moves to the determined optimum lighting position.

Optimal lighting conditions are set in the above series of steps. That is, the light source unit 42 is set at the optimum position for detecting the defect (the position where the contrast of the shadow of the defect appears most clearly). After this, the actual inspection is performed.

The actual inspection is performed according to the following procedure. First, the work W to be inspected is set on the stage 20. Next, the light source unit 42 is turned on to irradiate the work W with illumination light. Next, the work W is imaged by the camera 30. The image data obtained by imaging is used to inspect for defects. The light source unit 42 may be always on.

According to the surface inspection device 1 of the present embodiment, since the work W is imaged from an oblique angle, defects such as minute irregularities can be detected satisfactorily. In addition, by changing (variable) the way the illumination light is applied, it is possible to capture an image for inspection under the optimum illumination environment. Further, according to the surface inspection device 1 of the present embodiment, in the image pickup device 10, the entire work W can be captured within the depth of field and can be imaged at one time, so that the inspection can be performed efficiently. Further, according to the surface inspection device 1 of the present embodiment, since the image pickup device 10 can capture an image facing the work W, the inspection can be performed without performing a process of eliminating the distortion of the image.

[Modification example]
In the present embodiment, the light source unit 42 is moved linearly, but it may be moved in an arc shape. As a result, the direction of the main ray can also be changed.

Further, when the position of the light source unit (light source unit 42) of the illumination light is changed, the configuration may be changed continuously or intermittently. The same applies to the case where the direction of the main light beam of the illumination light irradiating the subject is changed, and the configuration can be changed continuously or intermittently.

The light source unit 42 may be configured so that the intensity of the emitted illumination light can be changed.

Further, in the above embodiment, the illumination position is optimized in advance to inspect the work, but the work is continuously imaged while changing the illumination position, and the obtained image data is used to inspect the work. It can also be configured to inspect.

[Second Embodiment]
In the surface inspection apparatus of the above embodiment, by moving the light source unit (light source unit 42), the relative position of the light source unit with respect to the work is changed, and the method of irradiating the illumination light is changed.

In the surface inspection apparatus of the present embodiment, a plurality of light source units are arranged and the light source unit to be turned on is changed to change the method of irradiating the illumination light.

Since the configuration other than the lighting device is the same as the surface inspection device of the above embodiment, only the configuration of the lighting device will be described here.

FIG. 11 is a side view of the lighting device of the present embodiment. FIG. 12 is a plan view of the lighting device.

The lighting device 40 has a plurality of light source units 42a to 42j. The configurations of the light source units 42a to 42j are the same as those of the light source unit 42 of the lighting device 40 according to the first embodiment. That is, it has a line-shaped light source 43 in which a plurality of light emitting elements 43a are arranged in a line shape.

The light source units 42a to 42j are arranged above the stage 20 and are arranged at regular intervals along the y-axis. In each of the light source units 42a to 42j, the direction of the main light beam is set perpendicular to the work mounting surface 20a. Therefore, the illumination light is irradiated perpendicularly to the work W.

Each of the light source units 42a to 42j is individually controlled to emit light from the light source 43. The light emission is controlled by the surface inspection device main body. That is, the illumination control unit 112 individually controls the light emission of the light source 43.

According to the lighting device 40 having the above configuration, by changing the light source units 42a to 42j to be turned on, it is possible to change the method of applying the lighting light to the work W mounted on the stage 20.

The following procedure is used to determine the optimum lighting conditions. First, the light source units 42a to 42j are turned on in order to image the work for determining the illumination position. From the obtained image data, the image data in which the contrast of the shadow of the defect appears most clearly is specified. The positions of the light source units 42a to 42j that are lit when the image data is imaged are determined as the optimum illumination positions.

The plurality of light source units 42a to 42j may be turned on in combination. That is, the light source units 42a to 42j do not necessarily light only one, but may be configured to light and use a plurality of light source units 42a to 42j at a time. It is preferable to identify the condition in which the contrast of the shadow of the defect appears most clearly and turn it on.

Further, also in the present embodiment, it is preferable to appropriately perform image processing on the image data obtained by imaging to determine the optimum lighting conditions.

[Modification example]
FIG. 13 is a side view showing a modified example of the lighting device of the present embodiment.

As shown in the figure, in the lighting device 40 of this example, a plurality of light source units 42a to 42j are arranged in an arc shape. By arranging the plurality of light source units 42a to 42j in an arc shape in this way, it is possible to irradiate the illumination light by changing the position of the light source portion of the illumination light and at the same time changing the direction of the main ray of the illumination light.

[Third Embodiment]
The configuration of the lighting device of the surface inspection device of the present embodiment is different from that of the surface inspection device of the first embodiment. In the lighting device of the present embodiment, the point-shaped or planar light source parts are arranged in a matrix, and the position of the light source part relative to the work is changed by changing the light source part to be lit, and the illumination light is applied. Change the direction.

Since the configuration other than the lighting device is the same as the surface inspection device of the above embodiment, only the configuration of the lighting device will be described here.

FIG. 14 is a plan view of the lighting device of the present embodiment.

The lighting device 40 has a plurality of light source units 42 [ij] (i = 1, 2, ..., J = 1, 2, ...). Each light source unit 42 [ij] has a point-shaped light source. In the present embodiment, a plurality of light emitting elements 43a are collectively arranged to form a point-shaped light source 43.

The plurality of light source units 42 [ij] are arranged in a matrix along a plane (xy plane) parallel to the work mounting surface 20a. In each light source unit 42 [ij], the direction of the main light beam is set perpendicular to the work mounting surface 20a. Therefore, each light source unit 42 [ij] irradiates the illumination light perpendicularly to the work W.

Each light source unit 42 [ij] is individually controlled to emit light from the light source 43. The light emission is controlled by the surface inspection device main body. That is, the illumination control unit 112 individually controls the light emission of the light source 43.

The following procedure is used to determine the optimum lighting conditions. First, the light source unit 42 [ij] is turned on in order to image the work for determining the illumination position. From the obtained image data, the image data in which the contrast of the shadow of the defect appears most clearly is specified. The position of the light source unit 42 [ij] that is lit when the image data is imaged is determined as the optimum illumination position.

The plurality of light source units 42 [ij] may be turned on in combination. For example, the light source unit 42a may be turned on and used in units of columns or rows.

[Modification example]
Also for the lighting device of the present embodiment, a configuration in which a plurality of light source units are arranged in an arc shape can be adopted. In particular, for the lighting device of the present embodiment, a configuration arranged in a dome shape can be adopted. That is, it is possible to adopt a configuration in which a plurality of light source units are arranged in a matrix on a hemispherical surface.

[Fourth Embodiment]
The configuration of the lighting device of the surface inspection device of the present embodiment is different from that of the surface inspection device of the first embodiment. The lighting device of the present embodiment changes the direction of the main light beam of the light source unit to change the method of applying the illumination light to the work.

Since the configuration other than the lighting device is the same as the surface inspection device of the above embodiment, only the configuration of the lighting device will be described here.

FIG. 15 is a side view of the lighting device of the present embodiment. FIG. 16 is a plan view of the lighting device of the present embodiment.

In the lighting device 40 of the present embodiment, the light source unit 42 is provided so as to be swingable, and by changing the direction of the light source unit 42, the direction of the main light beam is changed and the method of irradiating the illumination light is changed.

The lighting device 40 of the present embodiment includes a light source unit 42 and a swing mechanism 50 of the light source unit 42.

The configuration of the light source unit 42 is the same as that of the light source unit 42 of the lighting device 40 of the first embodiment. That is, it has a line-shaped light source 43 in which a plurality of light emitting elements 43a are arranged in a line shape.

The swing mechanism 50 includes a support portion that swings the light source unit 42 (swing freely) and a swing drive unit that swings the light source unit 42. The support portion includes shafts 52 provided at both ends of the light source unit 42, and bearings 54 that support the shaft 52. The swing drive unit is composed of a motor 56 that rotationally drives the shaft 52. The motor 56 is configured to be rotatable in the forward and reverse directions. When the shaft 52 is rotated by the motor 56, the light source unit 42 is tilted according to the amount of rotation. As a result, the direction of the illumination light (direction of the main light beam) emitted from the light source unit 42 is switched.

According to the illumination device 40 having the above configuration, by changing the angle of the light source unit 42, the direction of the illumination light emitted from the light source unit 42 (the direction of the main light beam) changes, and the way the illumination light hits the work changes. ..

The following procedure is used to determine the optimum lighting conditions. First, the work for determining the angle is imaged while changing the angle of the light source unit 42. The work for determining the angle is the same as the work for determining the illumination position. From the obtained image data, the image data in which the contrast of the shadow of the defect appears most clearly is specified. The angle at which the image data is captured is determined as the optimum illumination angle (angle of the light source unit 42).

[Modification example]
In the present embodiment, the work is irradiated with the illumination light from a fixed position, but the irradiation position may be changed. That is, the position of the light source unit may be changed as in the lighting device of the first embodiment. In this case, the light source unit may be moved linearly or may be moved on an arc.

[Fifth Embodiment]
The configuration of the lighting device of the surface inspection device of the present embodiment is different from that of the surface inspection device of the first embodiment. Since the configuration other than the lighting device is the same as the surface inspection device of the above embodiment, only the configuration of the lighting device will be described here.

FIG. 17 is a side view of the lighting device of the present embodiment.

The lighting device of the present embodiment is capable of changing the orientation of the individual light source units 42a to 42j in the lighting device of the second embodiment (see FIGS. 12 and 13). The individual light source units 42a to 42j are supported so that the support portion and the swing drive portion can swing (swing).

According to the lighting device 40 of the present embodiment, the position of the light source of the illumination light with respect to the work can be changed by changing the light source units 42a to 42j to be turned on. Further, by changing the directions (angles) of the lit light source units 42a to 42j, the direction of the main light beam of the illumination light irradiating the work can be changed.

As described above, in the illuminating device of the present embodiment, both the position of the light source portion of the illuminating light and the direction of the main ray can be adjusted. This makes it possible to set more detailed lighting.

[Modification example]
Even when the point-shaped or planar light source units are arranged in a matrix, the angles of the individual light source units may be changed. That is, the light source unit here may be configured to be swingable. In this case, it is preferable to be able to swing in multiple directions as well as in one direction.

[Sixth Embodiment]
FIG. 18 is a diagram showing a schematic configuration of the surface inspection apparatus of the present embodiment.

The surface inspection device 1 of the present embodiment includes a rotation mechanism of the stage 20, and the stage 20 rotates. The configuration other than the stage is the same as that of the surface inspection device 1 of the first embodiment. Therefore, in the following, only the configuration of the stage 20 and the action and effect of the rotation of the stage 20 will be described.

As shown in FIG. 18, the stage 20 has a rotating shaft 22 in the center, and the rotating shaft 22 is rotatably supported by an installation portion of the stage 20 via a bearing 24. A motor 26 is connected to the rotating shaft 22. By driving the motor 26, the stage 20 rotates.

According to the surface inspection device 1 of the present embodiment, the work W can be inspected by imaging the work W from a plurality of directions. Specifically, first, the work W is imaged from the first direction, and the first inspection is performed. After that, the stage 20 is rotated by 180 °, the work is imaged from the second direction, and the second inspection is performed. As described above, according to the surface inspection apparatus 1 of the present embodiment, the work W can be imaged a plurality of times from different directions while the work W is placed on the stage 20, and the work W can be inspected a plurality of times. This enables a more accurate inspection.

[7th Embodiment]
FIG. 19 is a diagram showing a schematic configuration of the surface inspection apparatus of the present embodiment.

The surface inspection device 1 of the present embodiment has a plurality of cameras 30a and 30b that image the work W. It is the same as the surface inspection device 1 of the first embodiment, except that it has a plurality of cameras 30a and 30b. Therefore, in the following, only the arrangement of the cameras and the effects of having a plurality of cameras will be described.

FIG. 20 is a perspective view showing the arrangement of cameras.

The surface inspection device 1 of the present embodiment has two cameras 30a and 30b (first camera 30a and second camera 30b). The configurations of the cameras 30a and 30b are the same as those of the camera 30 of the first embodiment.

The two cameras 30a and 30b are arranged on opposite sides of the stage 20 having a rectangular shape. Specifically, as shown in FIG. 20, the first camera 30a is arranged at the center of the right side of the stage 20 in the figure, and the second camera 30b is arranged at the center of the left side of the figure. To. As shown in FIG. 19, the first camera 30a images the work W from diagonally upward to the right. As shown in FIG. 19, the second camera 30b images the work W from diagonally upward to the left. Both the first camera 30a and the second camera 30b image the same range (including a range that is considered to be substantially the same). That is, the first camera 30a and the second camera 30b are set so that the imaging ranges overlap. In the present embodiment, the work mounting surface 20a is set as the imaging range.

According to the surface inspection device 1 of the present embodiment configured as described above, the work W can be imaged from a plurality of directions at one time. As a result, the work W can be inspected efficiently.

FIG. 21 is a diagram showing a modified example of the surface inspection device of the present embodiment.

This example is an example in which four cameras 30a to 30d are used. The cameras 30a to 30d are arranged on each side of the rectangular stage 20. As a result, the work can be imaged from four directions at a time. Furthermore, multiple cameras can be used.

[Eighth Embodiment]
In the above embodiment, the lighting device side has a configuration in which the lighting method is changed by changing the direction of the light source unit (direction of the main light ray) and / or the position of the light source unit.

In the present embodiment, the lighting device side is configured to irradiate the illumination light from a fixed position, and the stage and the camera are moved in conjunction with each other to change the method of irradiating the illumination light.

FIG. 22 is a schematic view showing the configuration of the image pickup apparatus of this embodiment.

As shown in the figure, the stage 20 and the camera 30 are installed on the same base frame 60. The base frame 60 has a rectangular flat plate shape, and has an axis 62 parallel to the x-axis at one end in the y-axis direction. The base frame 60 is swingably supported by the bearing 64 via its shaft 62. The other end of the base frame 60 in the y-axis direction is supported by the cylinder 66. The base frame 60 swings around the shaft 62 by expanding and contracting the shaft of the cylinder 66. As a result, the stage 20 and the camera 30 are linked and tilted. That is, the stage 20 and the camera 30 are integrally tilted. The cylinder 66 is an example of a drive unit. The stage 20 of the present embodiment is provided with a mechanism (vacuum suction mechanism, electrostatic suction mechanism, etc.) for sucking and holding the work W.

The lighting device 40 irradiates the work on the stage with illumination light from a fixed position. In the present embodiment, as shown in FIG. 22, the light source unit 42 is installed at a position diagonally above the left side of the stage 20 and irradiates the illumination light diagonally above the left side. The configuration of the light source unit 42 is the same as that of the light source unit 42 of the lighting device 40 of the first embodiment.

According to the surface inspection device 1 of the present embodiment configured as described above, when the cylinder 66 is driven and the base frame 60 is tilted, the stage 20 and the camera 30 are tilted in conjunction with each other. As a result, the way the illumination light emitted from the light source unit 42 hits changes. Identify the optimum tilt angle and inspect the workpiece at that angle.

In this way, the stage 20 and the camera 30 can be moved in conjunction with each other to change the way the illumination light is applied.

In the present embodiment, the stage 20 and the camera 30 are tilted in conjunction with each other to change the way in which the illumination light is applied. In addition, the stage 20 and the camera 30 are moved in conjunction with each other for illumination. It is also possible to change the way the light is applied.

Further, in the above embodiment, it is inclined in only one direction, but it may be inclined in multiple directions to change the way of illuminating the illumination light.

Further, in the above-described embodiment, the illumination light is irradiated from a fixed position, but the illumination device side may also be configured to be movable or tilted.

[Other embodiments]
[Inspection target]
In the above embodiment, the case of inspecting a single-wafer work is described as an example, but the present invention can also be applied to the case of inspecting a strip-shaped work.

FIG. 23 is a diagram showing an example of the configuration of an imaging device when inspecting a strip-shaped work.

The strip-shaped work W is continuously conveyed in a horizontal posture at a constant speed in one direction (for example, is conveyed by a roll-to-roll method).

The camera 30 is installed at a position at the same height as the surface of the work W, and the surface of the work W (image acquisition surface) is set as the focusing surface. The imaging range PA of the camera 30 is preferably set to a range in which the entire width direction of the work W (direction orthogonal to the transport direction) can be imaged at one time.

At the time of inspection, the lighting device 40 is set to the optimum lighting state, and the work W is imaged. The imaging is performed in synchronization with the transport of the work W, and the work W is continuously imaged while partially overlapping the transport directions.

Further, in the above embodiment, the case of inspecting the surface of the sheet-shaped work has been described as an example, but the surface inspection apparatus of the present invention can also be applied to the case of inspecting the surface of a three-dimensional object. In this case, the focal plane is set according to the plane to be inspected.

[camera]
The camera may be provided with a focus adjustment mechanism. In this case, for example, the entire imaging optical system is moved along the optical axis Z to adjust the focus. Alternatively, the image sensor 33 is moved back and forth along the optical axis to adjust the focus.

[Lighting device]
In the above embodiment, the case where the LED is used as the light source has been described as an example, but the type of the light source is not limited to this. The light source can be appropriately selected according to the inspection target and the like.

1 Surface inspection device 10 Imaging device 20 Stage 20a Work mounting surface 22 Rotating shaft 24 Bearing 26 Motor 30 Camera 30a to 30d Camera 31 Housing 31a Imaging window 32 Imaging optical system 33 Imaging element 40 Lighting device 42 Light source unit 42a to 42j Light source unit 42 [ij] Light source unit 43 Light source 43a Light emitting element 44 Moving mechanism 46a Guide rail 46b Slider 48a Feed screw 48b Motor 48c Nut 50 Swing mechanism 52 Axis 54 Bearing 56 Motor 60 Base frame 62 Axis 64 Bearing 66 Cylinder 100 Inspection device Main unit 101 CPU
102 RAM
103 ROM
104 HDD
106 Display unit 107 Input / output interface 108 Communication unit 111 Camera control unit 112 Lighting control unit 113 Image input unit 114 Image processing unit 115 Lighting condition determination unit 116 Inspection unit 117 Display control unit 118 Recording control unit 119 Communication control unit A Optical axis Near light beam B Light beam with maximum angle of view C1 Junction lens GF Front group of optical system GR Optical system Rear group I Intermediate image L1 lens (first lens)
L2 lens (second lens)
L3 lens (third lens)
L4 lens (4th lens)
L5 lens (fifth lens)
L6 lens (6th lens)
L7 lens (7th lens)
M1 Mirror Obj Object surface PA Imaging range RO Optical system Sim Imaging surface St Aperture aperture SI1 to SI3 Defects on the work surface reflected in the image of the work W Work WI1 Image of the work Image of WI2 Work image WI4 Work Image taken by Ymax Maximum image height Z Optical axes S11 to S18 Procedure for determining the optimum illumination position

Claims (16)

An imaging unit that has an imaging optical system in which the image acquisition surface is the in-focus surface, captures the subject within the imaging range within the depth of field, and images the subject at an angle to acquire image data.
An illumination unit in which the direction of the main ray of the illumination light irradiating the subject and / or the position of the light source unit of the illumination light is variable.
Imaging device equipped with. An image processing unit that performs image processing on the image data is further provided.
The image processing unit performs processing for emphasizing the difference in the image data caused by changing the direction of the main ray of the illumination light and / or the position of the light source unit of the illumination light.
The imaging device according to claim 1. The lighting unit
Light source and
The moving mechanism of the light source unit and
The light source unit is moved by the moving mechanism to change the position of the light source unit of the illumination light.
The imaging device according to claim 1 or 2. The illumination unit further includes a swing mechanism of the light source unit, and the swing mechanism changes the direction of the light source unit to change the direction of the main light beam of the illumination light.
The imaging device according to claim 3. The lighting unit
Light source and
The swing mechanism of the light source unit and
The swing mechanism changes the direction of the light source unit to change the direction of the main light beam of the illumination light.
The imaging device according to claim 1 or 2. The illumination unit includes a plurality of light source units, changes the light source unit to be turned on, and changes the position of the light source unit of the illumination light.
The imaging device according to claim 1 or 2. The illumination unit further includes a swing mechanism of the light source unit, and the swing mechanism changes the direction of the light source unit to change the direction of the main light beam of the illumination light.
The imaging device according to claim 6. A plurality of the light source units are arranged in a matrix.
The imaging device according to claim 6 or 7. A plurality of the light source units are arranged in an arc shape.
The imaging device according to any one of claims 6 to 8. A plurality of the imaging units in which the imaging range is set to overlap are provided.
The imaging device according to any one of claims 1 to 9. A holding unit that holds the subject and
The rotation mechanism of the holding part and
The imaging device according to any one of claims 1 to 10, further comprising. An imaging unit that has an imaging optical system in which the image acquisition surface is the in-focus surface, captures the subject within the imaging range within the depth of field, and images the subject at an angle to acquire image data.
An illumination unit that irradiates the subject with illumination light,
A holding unit that holds the subject and
A drive unit that moves or tilts the image pickup unit and the holding unit in conjunction with each other.
Imaging device equipped with. An image processing unit that performs image processing on the image data is further provided.
The image processing unit performs processing for emphasizing the difference in the image data caused by changing the direction of the main ray of the illumination light and / or the position of the light source unit of the illumination light.
The imaging device according to claim 12. The imaging optical system of the imaging unit includes one mirror having positive power and an optical system composed of a plurality of lenses having positive power in order from the object side, and the mirror and the optical system An intermediate image is formed between and
The imaging device according to any one of claims 1 to 13. The mirror and the optical system have a common optical axis and have a rotationally symmetric shape with the optical axis as the rotation axis.
The imaging device according to claim 14. The imaging device according to any one of claims 1 to 15.
An inspection unit that inspects the surface of the work using the image data acquired by the imaging unit, and an inspection unit.
Surface inspection device equipped with.

Images