JP7111370B2 - Defect inspection method - Google Patents

Description

The present invention relates to a defect inspection device and a defect inspection method.

In the manufacturing process of various members used for industrial purposes, etc., there are cases where processing oil or the like is used and remains attached to the members. In order to omit the step of cleaning the adhering oil when inspecting such a member, it may be necessary to inspect for defects while the oil is still adhered to the member. Examples of these various members include cylinders and traveling system parts of automobiles, photoreceptor drums and fixing rollers of electrophotographic image forming apparatuses, etc., and members having shapes such as cylindrical and columnar shapes are also widely used. .

It is difficult to inspect such members and the like, and a visual inspection or the like is performed by a trained inspector. However, in the case of visual inspection, etc., the determination may vary depending on the amount of oil adhered, the degree of training, physical condition, and the like. In addition, it may not be possible to make a visual distinction due to adhesion of oil.

Patent Document 1 describes a glossing agent for the surface of an inspection object for giving gloss to the surface of the inspection object for surface inspection using a retroreflective screen, in which the surface tension, viscosity, and the surface of the inspection object under the working environment A contact angle controlled test object surface brightener is disclosed.

In Patent Document 2, the image input means includes a first camera whose aperture is adjusted according to the oil-attached portion and the light reflectance, and an aperture whose aperture is adjusted corresponding to the light reflectance of the oil-free portion. A surface defect inspection apparatus with a second camera is disclosed.

Patent Document 3 discloses an oil state determination unit that determines the oil adhesion state based on the surface state of the surface to be inspected from the surface inspection unit, and an illumination light irradiation angle based on the oil adhesion state from the oil state determination unit. oil countermeasure instruction means for outputting, as a countermeasure instruction, at least a change in illumination light irradiation angle or a change in the imaging angle among the change in the angle of the oil, the change in the imaging angle, and the control of the amount of oil adhered to the surface to be inspected; discloses a surface defect inspection apparatus provided with illumination/imaging control means for controlling the angle and height of at least one of the illumination means and the imaging means based on the countermeasure instruction.

JP-A-6-3286 JP-A-11-108641 Japanese Unexamined Patent Application Publication No. 2001-28788

Colorless, transparent, and colored, transparent oils with high cleanliness such as rust preventive oils, cleaning oils, and processing oils are used in the manufacturing processes of various members. However, when inspecting a member to which these substances adhere, the oil film causes diffuse reflection or specular reflection of the inspection light, making it difficult to detect defects such as scratches on the member that are inside the oil film. .

In Patent Documents 1 to 3, etc., oil is intentionally attached, and defect detection is performed by specifying the oil-attached portion. In some cases, it is difficult to identify the oil adhesion site. Thus, there is a need for a defect inspection method that suppresses the effects of oil adhering to members.
Under such circumstances, an object of the present invention is to provide a defect inspection apparatus that can detect defects such as scratches on members without removing the oil by reducing the effect of the oil even when it is attached. and to provide a defect inspection method.

As a result of earnest research to solve the above problems, the inventors of the present invention have found that the following inventions meet the above objects, and have completed the present invention. That is, the present invention relates to the following inventions.

<1> A defect inspection apparatus for the surface of a member, comprising: a line camera for imaging an inspection portion of the member toward the axis in the height direction of the member; a first illumination that illuminates the member, and a second illumination that illuminates the member from an angle different from the first illumination toward the axis in the height direction of the member,
A first angle (θ1) between an axis along which the line camera images the member and an axis along which the first illumination irradiates toward the axis in the height direction of the member is an angle of 5 to 15 degrees. and linearly irradiating along the height direction of the member,
A second angle (θ2) formed between an axis along which the line camera images the member and an axis along which the second illumination irradiates toward the axis in the height direction of the member is an angle of 20 to 40 degrees. in a direction opposite to the first angle and linearly irradiating along the height direction of the member.
<2> The defect inspection apparatus according to <1>, wherein the member is a columnar member to which oil adheres.
<3> When viewed in the horizontal direction from the axis along which the line camera captures the image of the inspection site, the angle formed by the axis along which the line camera captures the image and the axis along which the second illumination illuminates is 0 to 60 degrees. The defect inspection apparatus according to <2>, which irradiates from a direction.
<4> The defect inspection apparatus according to any one of <1> to <3>, further comprising member rotating means for rotating the member in the circumferential direction.
<5> having an image analysis unit that analyzes an image captured by the line camera;
The defect inspection apparatus according to any one of <1> to <4>, wherein the line camera captures an image while rotating the member, thereby capturing an image of the peripheral surface of the member.
<6><1> to <5> having a determination unit that determines the presence or absence of a defect by comparing the brightness of the image captured by the line camera with a brightness threshold value for determining the presence or absence of a defect in the member. The defect inspection device according to any one of the above.
<7> A defect inspection method for the surface of a member, comprising:
a first illumination that illuminates the member toward the axis in the height direction of the member; and a second illumination that illuminates the member from an angle different from that of the first illumination toward the axis in the height direction of the member. an irradiation step of irradiating with a second illumination;
an imaging step of imaging the member irradiated in the irradiation step with a line camera;
A first axis formed by an axis along which the line camera images images toward the axis in the height direction of the member, and an axis along which the first illumination illuminates the member toward the axis in the height direction of the member. irradiate linearly along the height direction of the member at an angle (θ1) of 5 to 15 degrees,
A second angle (θ2 ) is irradiated linearly along the height direction of the member at an angle of 20 to 40 degrees.

According to the defect inspection apparatus and defect inspection method of the present invention, defects such as scratches on members can be detected.

1 is a schematic diagram of a first embodiment of a defect inspection apparatus according to the present invention; FIG. It is a top view which shows the positional relationship of the 1st optical system of the defect inspection apparatus which concerns on this invention. It is a side view which shows the positional relationship of the 1st optical system of the defect inspection apparatus which concerns on this invention. It is a side view which shows the positional relationship of the 2nd optical system of the defect inspection apparatus which concerns on this invention. It is a side view which shows the positional relationship of the modification of the second optical system of the defect inspection apparatus which concerns on this invention. It is a flow chart showing an example of a defect inspection process by the defect inspection apparatus according to the present invention. It is a figure which shows an example of the test object of this invention. FIG. 10 is a diagram showing an example of processing and displaying the defect inspection result of the surface of the columnar member as surface information according to the embodiment of the present invention; FIG. 10 is a diagram showing an example in which defect inspection results of the surface of a columnar member are processed as surface information and displayed according to the reference example of the present invention; FIG. 10 is a diagram showing an example in which defect inspection results of the surface of a columnar member are processed as surface information and displayed according to the reference example of the present invention; FIG. 10 is a diagram showing an example in which defect inspection results of the surface of a columnar member are processed as surface information and displayed according to the reference example of the present invention;

Embodiments of the present invention will be described in detail below. is not limited to the contents of In this specification, when the expression "~" is used, it is used as an expression including the numerical values before and after it.

[Defect inspection device of the present invention]
A defect inspection apparatus of the present invention is an apparatus for inspecting defects on the surface of a member, comprising a line camera for imaging an inspection portion of the member toward the axis in the height direction of the member; A first illumination that illuminates the member toward the axis, and a second illumination that illuminates the member from an angle different from the first illumination toward the axis in the height direction of the member. , a first angle (θ1) between an axis along which the line camera images the member and an axis along which the first illumination illuminates the member toward the axis in the height direction is 5 to 15 degrees; At an angle, the light is emitted linearly along the height direction of the member, and the line camera illuminates the axis along which the member is imaged, and the second illumination irradiates toward the axis of the member in the height direction. The second angle (θ2) with the axis is 20 to 40 degrees and is in the direction opposite to the first angle, and the member is linearly irradiated along the height direction.
With such a configuration, it is possible to detect defects in the member while suppressing the influence of the presence or absence of oil adhesion. In addition, since this defect detection is performed using an image, the member can be detected non-destructively, and there is no possibility that the defect will be scratched by the inspection. Therefore, the member after inspection can be used as it is.

[Defect inspection method of the present invention]
A defect inspection method of the present invention is a defect inspection method for the surface of a member, comprising: a first illumination for illuminating the member toward the axis in the height direction of the member; An irradiation step of irradiating the member toward the center with a second lighting that irradiates the member from an angle different from the first lighting, and an imaging step of imaging the member irradiated in the irradiation step with a line camera. and an axis along which the line camera captures images toward the axis in the height direction of the member, and an axis along which the first illumination illuminates the member toward the axis in the height direction of the member. The first angle (θ1) is an angle of 5 to 15 degrees, and the line camera irradiates linearly along the height direction of the member, and the line camera picks up the axis in the height direction of the member. , along the height direction of the member at a second angle (θ2) between 20 and 40 degrees with the axis that the second illumination irradiates toward the axis in the height direction of the member Irradiate linearly.
With such a configuration, it is possible to detect defects in the member while suppressing the influence of the presence or absence of oil adhesion.
The defect inspection method of the present invention can be performed using the defect inspection apparatus of the present invention, and configurations corresponding to each in the present application can be used mutually.

The present inventors have studied defect inspection by optical means for various members to which oil adheres during the manufacturing process, which have conventionally been visually evaluated or inspected by wiping off oil or cleaning. As a result, as will be described in detail later in the examples, etc., when inspected by ordinary optical means, the oil is reflected due to irregular reflection or specular reflection from the oil-adhered part, and it may be difficult to inspect the member itself for defects. was confirmed.

However, it has been confirmed that even when such oil adheres, reflection of the oil can sometimes be suppressed by adjusting the illumination angle or the like. However, when the inspected portion is irradiated with one illumination, there are cases where the defect is not detected, or the difference in brightness between the defect and other portions is small and it is very difficult to distinguish the defect. Depending on the shape of the member, when light is irradiated, the reflected light scatters at various angles. is thought to affect

The inventors of the present invention have found that when inspecting such a member for defects, using a line camera enables imaging of a portion where the brightness of the scattered light from the columnar member is relatively stable. In addition to the first illumination that illuminates the inspection area from a predetermined angle, a second illumination is used to illuminate the inspection area from an angle different from that of the first illumination, thereby reducing the effects of oil adhesion and reducing defects. It was found that an image that is easy to detect can be captured.

[Defect inspection device (100)]
A first embodiment of a defect inspection apparatus according to the present invention will be described with reference to FIG. 1 and the like. FIG. 1 is a diagram showing an overview of the configuration of a defect inspection apparatus 100. As shown in FIG. The defect inspection apparatus 100 has a first illumination 11 , a second illumination 21 and a line camera 31 . The defect inspection apparatus 100 is an apparatus for inspecting defects of the member 4 . The member 4 is fixed to the fixing means 51 of the member 4 and the fixing means 51 is provided on the rotating means 52 . An image picked up by the line camera 31 is detected by the image detection unit 60 , analyzed by the image analysis unit 71 and the determination unit 72 , and the presence or absence of defects is determined. Captured images, analyzed images, defect determination results, and the like are stored in the memory 90 as appropriate. Hereinafter, the direction in which the member 4 in FIG. 1 is imaged by the line camera 31 is defined as the X direction, the direction orthogonal to the X direction in the horizontal plane is defined as the Y direction, and the direction orthogonal to the horizontal planes of the X and Y directions is defined as the Z direction.

[First optical system 101]
FIG. 2 is a diagram showing a specific configuration example of the arrangement of the optical system in the defect inspection apparatus. The first illumination 11 and the second illumination 21 irradiate light toward the axis 42 in the height direction of the member 4 , and the line camera 31 images the inspection site 413 of the member 4 . The first illumination 11, the second illumination 21, and the line camera 31 in this defect inspection apparatus are called an optical system in the present application. FIG. 2 is a diagram showing an example of the first optical system 101, and is a plan view (seen from the Z direction) of the first optical system 101. As shown in FIG.

[First illumination 11]
The first illumination 11 is illumination for irradiating the member 4 with light. The first lighting 11 is preferably lighting that illuminates the member 4 linearly. The first lighting 11 is LED line lighting or equivalent to LED line lighting, in which light sources such as LEDs arranged in a line are used, and light is collected in a line by an appropriate light collecting means to irradiate pseudo-parallel light. Illumination whose optics are designed to provide illuminance is preferred. By using LED line lighting or the like, it is possible to irradiate moderately bright and wide light, and improve the S/N ratio.

The first illumination 11 can be appropriately selected according to the imaging of the line camera 31, the state of the member 4, its defect, and the like. The wavelength of the light may be a single wavelength of light in the wavelength range from near ultraviolet to near infrared, or may be a mixed color or white. Light having a peak wavelength in the vicinity of a low wavelength of 350 to 650 nm is particularly preferred. If there is a peak on the high-wavelength side, the light may circulate and irradiate near the defect, reducing the luminance difference and making it difficult to detect the defect. Moreover, polarized light such as linearly polarized light or elliptical polarized light may be irradiated, or natural light may be irradiated.

[Second lighting 21]
The second lighting 21 is lighting that irradiates the member 4 with light from an angle different from that of the first lighting 11 . As the second illumination 21, illumination that emits light linearly can be used in the same manner as the first illumination. When illuminating the member 4 , the illuminance may be different from that of the first illumination 11 . It is preferable that the second lighting 21 has a higher illuminance than the first lighting 11 . Further, it is more preferable that the second illumination 21 uses line illumination with higher directivity than the first illumination 11 .

[Line camera 31]
The line camera 31 images an inspection portion 413 of the member 4 . The line camera 31 is arranged at an angle for imaging toward the axis 42 in the height direction of the member 4 . The line camera 31 has photodiodes arranged in series and captures a linear image of an object. A CCD, a CMOS, or the like can be appropriately used as the line camera. When the line camera 31 captures an image of the inspection site 413, even if the surface of the member 4 has a curved surface or unevenness in the shape of the member, the luminance difference that is detected due to these basic shapes can be suppressed. It can be imaged.
The number of imaging pixels, scan rate, and the like of the line camera 31 can be appropriately set according to the size and type of the member 4, the type of flaw to be observed, the rotation speed of the rotating means, and the like. For example, the number of imaging pixels can be 500 pixels or more, 1000 pixels or more, or 2000 pixels or more. In particular, the line camera 31 has a pixel size of about 30 μm square (30 μm×30 μm) or less so that defects such as blowholes and hairlines when the member 4 is a metal member can be detected and the size of these defects can be determined. It is preferable that an image can be captured with a size of 15 μm, and more preferably, with a finer pixel size such as 15 μm square, 10 μm square, or 8 μm square.

[Member 4]
The member 4 to be inspected for defects may have any shape. The member 4 may be a hollow member, a solid member, or the like, and may have a columnar shape such as a cylinder, a cylinder, or a polygonal column. In addition, it may have steps or grooves. The material of the member 4 is not particularly limited, and metals, resins, ceramics, glass tubes, etc. can be used. In addition, it may be appropriately surface-treated, or plated or the like may be used. The member 4 can be formed by appropriately combining casting, cutting, injection molding, etc. according to each material and application.

In particular, even if oil adheres to the member, the inspection can be performed while suppressing the influence of the oil, so that the object to be inspected can be an object to which oil may adhere. It is preferable that the oil is highly transparent, such as washing oil or processing oil.

The inspection region 413 is a linear portion imaged by the line camera 31 . An inspection portion 413 is set in the height direction of the member 4 . When the member 4 has a columnar shape or the like, it is possible to inspect the entire side surface of the member 4 for defects by capturing an image with the line camera 31 while being rotated in the circumferential direction by a rotating means or the like, which will be described later.

A first illumination 11 , a second illumination 21 and a line camera 31 are arranged based on the axis 42 of the member 4 . When the cross-sectional shape of the member 4 is closest to a circle, the axial center 42 is substantially the center of the cross-sectional circle when viewed from the front direction of the cross-sectional view. Even if the cross-sectional shape is not completely circular, or if the irradiated light is slightly deviated from the axis, the effect of the present invention can be obtained by wraparound light and the like. can be treated as having In this case, the point of the axis of the member 4 is defined as the axis A0, and the cross-sectional area of the cross section of the member 4 is obtained. Therefore, the range from A0 to φ0/10 (preferably φ0/20) can be set as the range corresponding to the axis 42 . Then, the first illumination 11 and the second illumination 21 are arranged to illuminate the range treated as this axis.

[First optical system 101]
2 and 3 are diagrams for explaining the arrangement of the first optical system 101 in more detail. The first optical system 101 inspects the inspected portion 413 of the member 4 . The first optical system 101 is arranged such that the line camera 31, the first illumination 11, and the second illumination 21 are at predetermined positions.
In the first optical system 101, the line camera 31 and the first illumination 11 are arranged at a first angle θ1, and the line camera 31 and the second illumination 21 are arranged at a second angle θ2. be done. Also, in the first optical system 101, the first illumination 11, the second illumination 21, and the line camera 31 are arranged in a horizontal plane (FIG. 3).

[First angle (θ1)]
The first angle θ1 is a position seen from a direction orthogonal to the imaging axis of the line camera 31, and in plan view, the axis x0 as a reference for the line camera 31 to image the axis 42 of the member 4 and the first angle θ1. It is an angle formed with the axis x1 with which one illumination 11 irradiates toward the axis 42 of the member 4 . This first angle θ1 is 5 to 15 degrees. By irradiating in this range, even if oil adheres to the member 4, the effect of the oil can be suppressed and defects on the surface of the member itself to which the oil adheres can be inspected. More preferably, the first angle θ1 is an angle of 8 to 12 degrees.

If the angle θ1 is too small, it may be difficult to install the first illumination 11 and the line camera 31, or the difference in luminance between the defect and the normal portion is small, making it difficult to detect the defect. Moreover, the light reflected from the member 4 and incident on the line camera 31 may become strong, causing halation.

On the other hand, if the angle .theta.1 is too large, the illumination of the inspection site 413 will not be sufficiently generated, and the illuminance when viewed from the axis where the line camera 31 is going to image will decrease, and the effect of the S/N ratio will not be obtained. In particular, if the angle is larger than 45 degrees, diffuse reflection/regular reflection from the oil becomes strong, and the oil may be reflected in the line camera 31 .

[Second angle θ2]
The angle θ2 is the angle between the axis x0 that is the reference for the line camera 31 to image the axis 42 of the member 4 and the axis x2 that the second illumination 21 irradiates toward the axis 42 of the member 4 . This second angle θ2 is in the opposite direction to the first angle θ1. That is, when the first angle θ1 is a positive angle when the first optical system 101 is viewed from above, the second angle θ2 is a negative angle. Also, when the first angle θ1 is a negative angle, the second angle θ2 is a positive angle.

The second angle θ2 is 20-40 degrees. By irradiating in this range, even if oil adheres to the member 4, the effect of the oil can be suppressed and defects on the surface of the member itself to which the oil adheres can be inspected. In addition, due to the synergistic effect with the first illumination 11, it is easy to obtain a bright image with high brightness as a whole, and among them, defects have specific brightness and are easy to observe.

If the angle θ2 is too small, it may be difficult to install the second illumination 21 and the line camera 31, or the difference in brightness between the defect and the normal portion is small, making it difficult to detect the defect. Moreover, the light reflected from the member 4 and incident on the line camera 31 becomes strong, and halation may occur.

On the other hand, if the angle .theta.2 is too large, the illumination of the inspected portion 413 will not be sufficient, and the effect of the S/N ratio will not be obtained, making it difficult to detect defects.・The specular reflection becomes strong, and oil may be reflected in the line camera 31 .

When the member 4 is irradiated at the first angle θ1 and the second angle θ2, the optical axis X1 (X2) of the first illumination 11 (second illumination 21) is aligned with the irradiated portion 411 ( 412). This irradiation site 411 (412) is a different and distant position from the inspection site 413. FIG. Since the irradiation position and the inspection position are separated from each other, the irradiation light from the first lighting 11 (second lighting 21) is less likely to be reflected and scattered in the direction in which the line camera 31 captures an image. However, the light that has irradiated the irradiated portion 411 (412) wraps around the surface of the member 4 and illuminates the inspection portion 413 . If it is illuminated by such light that wraps around, the member 4 can be inspected even if oil or the like adheres to it, because the influence of scattering due to the irregular surface and interface caused by the oil can be suppressed. In addition, the amount of light that can be detected by the line camera 31 tends to be low due to the arrangement of the line camera 31 with respect to the axis that the line camera 31 picks up. By irradiating from different directions with one illumination, inspection can be performed with a light amount suitable for observing the surface state of the member 4 .

The distances between the member 4 and the first illumination 11 and the second illumination 21 are appropriately adjusted according to the size of the member 4 and the like. For example, when the diameter of the member 4 is φx, the distance from the axis 42 of the member 4 to the irradiation port 111 of the first illumination 11 and the irradiation port 211 of the second illumination 21 is 1.5 times φx. It can be about 30 times or about 2 times to 20 times. Alternatively, the distance between them may be about 5 cm to 1 m, or about 10 cm to 70 cm. If it is too close, it may be difficult for light to stray, and the inspection site 413 may not be sufficiently bright. Also, if the distance is too far, even if directivity light is used, it will gradually diffuse, and illumination with effective wraparound light may not be obtained or the illuminance may decrease.

[Second optical system 102]
FIG. 4 is a diagram for explaining the arrangement of the second optical system 102 in more detail. The second optical system 102 inspects the inspected portion 413 of the member 4 . The second optical system 102 is arranged so that the line camera 31, the first illumination 11, and the second illumination 21 are at predetermined positions.
The second optical system 102 has the first illumination 11 arranged at the first angle θ1 and the second illumination 21 arranged at the second angle θ2. The angles when these arrangements are viewed in plan are the same as those shown in FIG. 2 regarding the first optical system 101 .

In the second optical system 102, the first illumination 11 and the line camera 31 are arranged so that their respective imaging directions and optical axes are arranged horizontally in the height direction (z direction). ing. On the other hand, the second illumination 21 is arranged with its optical axis tilted at a predetermined angle in the height direction (in the Z direction).

[Angle θz1]
When the axis along which the line camera 31 captures the image of the member 4 is viewed from the horizontal direction, the direction of the axis z0 captured by the line camera 31 at the axis 42 of the member 4 and the optical axis z1 irradiated by the second illumination 21 form. It is preferable that the angle (θz1) is from a direction of 0 to 70 degrees. The first optical system 101 also arranges the second illumination 21 horizontally (θz1 is 0 degrees).

When the second illumination 21 illuminates the member 4 with an optical axis tilted in the height direction (z direction), the angle θz1 is preferably from 10 to 70 degrees. By tilting the second illumination 21 and illuminating it, a difference in the light-illuminated part is generated in uneven scratches that are difficult to change only by illuminating the light with high directivity from the horizontal direction, and shadows are generated, and defects are detected. easier to do. When the angle θz1 is 10 degrees or more, it becomes easier to detect unevenness flaws more remarkably. If the angle θz1 exceeds 70 degrees and is too large, it may be difficult to arrange the second illumination 21 . The angle θz1 may be 15 degrees or more, or 20 degrees or more. Also, the angle θz1 may be 60 degrees or less, or 50 degrees or less.

In addition, when the second illumination 21 is arranged in such a state that it is tilted in the height direction, it is preferable that the first illumination 11 is arranged substantially horizontally with the line camera 31 imaging axis z0. When light enters the scratches of the recesses, the light is diffusely reflected inside the recesses, and the brightness becomes high, making it easy to detect scratches. Sometimes. In such a case, the first illumination 11 emits light from a substantially horizontal direction, which is effective for such defect detection and defect detection according to the member shape. The term "substantially horizontal" can be set such that the angle formed by the optical axis of the first illumination device 11 with the axis z0 is 5 degrees or less, 3 degrees or less, or 1 degree or less.

FIG. 5 is a diagram showing a second optical system 102B showing a modified example of the second optical system 102. As shown in FIG. In the second optical system 102 of FIG. 4, the arrangement in which the second illumination 21 itself is tilted and its optical axis (z1) is tilted has been described. 21B itself has a configuration that irradiates obliquely from the illumination unit that irradiates the illumination light. In such a case as well, the tilt can be adjusted based on the optical axis z1 of the second illumination 21B.

[Fixing means (51)]
The fixing means 51 is means for fixing the member 4 . When the member 4 is tubular and has openings on the bottom surface and the top surface, it may be gripped from the inside with inner claws, or the openings of the member 4 may be arranged in a conical member having a tapered portion at the top. It is also possible to have a structure in which the inner diameter of the opening and the diameter of the weight match. Moreover, the surface side of the member 4 may be fixed by the outer claws, or the upper and lower parts may be pressed and fixed. The fixing means 51 fixes the member 4 at a predetermined position while the predetermined inspection site 413 is being inspected.

[Rotating Means (52)]
The fixing means 51 are provided on the rotating means 52 . The rotating means 52 is means for rotating the member 4 fixed to the fixing means 51 in the circumferential direction. The fixing means 51 can be rotated by rotating rollers, gears, or the like. The rotation of the rotating means 52 is sufficient as long as it can rotate corresponding to the inspection range of the member 4, and in the case of inspecting the entire circumference, it can be rotated by 360 degrees or more in the circumferential direction. Moreover, it is preferable that the position of the member 4 in the circumferential direction can be specified by controlling or detecting the position of rotation.

[Image detection unit (60)]
The image detection unit 60 is a part that detects information captured by the line camera 31 . Information about the image captured by the line camera 31 is appropriately transmitted to the image detection unit 60 as electrical information or the like by wire or wirelessly. Based on this information, it is detected as an image. The image detection unit 60 may obtain an image obtained by integrating luminance data of the same inspection site 413 captured by the line camera 31 .

[Image analysis unit (71), determination unit (72)]
The image analysis section 71 is a section that analyzes the image detected by the image detection section 60 . A linear image detected as luminance data or the like is analyzed as information in the circumferential direction corresponding to the inspection range through the line camera 31 and the image detection unit 60 while rotating the rotating means 52 as appropriate, and the entire inspection range is analyzed. can be an image of Further, the determining unit 72 determines whether or not there is a defect based on the brightness of the image captured by the line camera 31, using a threshold for determining whether or not there is a defect.

[Display (80)]
The display unit 80 is a portion that displays an image analyzed by the image analysis unit 71, analysis results, determination results of the determination unit 72, and the like. For example, the image detected by the image detection unit 60 may be subjected to only brightness correction or the like by the image analysis unit 71 and displayed as an image of a specific linear inspection region 413 . Further, the images picked up while rotating the rotating means 52 may be analyzed and the imaged result as an image of the inspection range may be displayed. Alternatively, the presence or absence of a defect may be determined using a threshold value for determining the presence or absence of a defect, and the determination result may be displayed. In addition, the evaluation conditions, information on members, and the like may be displayed together.

[Memory (90)]
The memory 90 is means for appropriately storing captured images, analyzed images, defect determination results, and the like.

[Defect inspection method (S100)]
FIG. 6 is a diagram showing an example of an inspection flow of a defect inspection method using the defect inspection apparatus 100. As shown in FIG.

First, an irradiation step S11 of irradiating the member 4 with the first lighting 11 and the second lighting 21 that irradiates the member 4 from an angle different from that of the first lighting 11 toward the axis 42 of the member 4 is performed.

An imaging step S21 of imaging the inspection site 413 with the line camera 31 is performed while this irradiation is maintained. The captured image is appropriately detected by the image detection unit 60 and stored in the memory 90 .

After imaging, a determination step S22 is performed to determine whether or not a predetermined range for defect inspection has been imaged. If the predetermined range has not been imaged, the rotating means 52 is rotated to move the inspected portion 413 in the circumferential direction, and a rotation step S23 is performed in which the next inspected portion 413 is arranged so as to be inspected. In this state, the imaging step S21 is performed. This is repeated until a predetermined range is imaged. When the image of the predetermined range is finished, the image capturing and rotation are finished. An image captured along with this rotation is also detected by the image detection unit 60 as appropriate and stored in the memory 90 .

After completion of imaging, an image analysis step S31 is performed in which the image stored in the memory 90 is analyzed by the image analysis unit 71 . This analysis assumes that the imaged results of the surface of the member 4 are arranged in a plane, and processes them as having shading and colors according to the luminance of the imaged image. and

Based on the analysis result, the determination unit 72 performs a determination step S41 for determining whether or not there is a defect by comparing it with a predetermined threshold value for detecting a defect. This threshold value is used when performing a so-called dark-field inspection in which the brightness of a normal part is low and the brightness of a defect is high. can be determined. The determination result is displayed on the display unit 80 in the display step S51, and the defect inspection of the member 4 is completed.

FIG. 7 shows an example of a member to be inspected in the present invention. The member in FIG. 7 is a columnar member to which oil adheres. In such an oily state, it may be difficult to detect defects on the oily surface.

A defect of a member is an abnormal portion of the surface, such as linear or planar unevenness in color or gloss, unevenness, etc., which is detected visually or physically. A representative defect is a series of concave scratches as shown in FIG. In particular, depending on the direction of the scratches on the part where the oil adheres, if it is irradiated with a single illumination, the surface reflection of the oil, the overall brightness is low, and the brightness of the defect is not sufficiently high. may be difficult to occur. According to the present invention, defects such as scratches can be inspected.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless the gist thereof is changed.

[Example 1]
A defect inspection apparatus using an optical system conforming to the second optical system 102B (FIG. 5), which is a modified example of the second optical system 102, was configured to evaluate the surfaces of members.
Line illumination of LEDs emitting blue (peak wavelength about 450 nm) quasi-parallel light was used as the first illumination and the second illumination. In addition, an image was detected using a line camera that detects approximately 8000 pixels in a line. For the line camera, the distance to the member, the photographing range, and the lens magnification were set so that each pixel could take an image of about 7 μm.
They were arranged so that the first angle θ1: 10° and the second angle θ2: 32°. In addition, the second illumination was to irradiate light obliquely in the height direction (Z direction), and the angle θz1 was set to 45°. Note that the first illumination is arranged in the horizontal plane and illuminates as in the case of the line camera.
· Member: A substantially cylindrical member with a diameter of 15 mm and a height of 200 mm, which was cast using metal, cut, and then subjected to step processing, was evaluated. In addition, processing oil (red oil) adheres to this member during the manufacturing process.
FIG. 8 shows an example of imaging in which the vicinity of the defect of the member according to Example 1 is enlarged. It is possible to confirm that elliptical scratches are continuous in a straight line around the part where the stepped processing is performed. Also, the leftmost scratch is a shallow scratch that is difficult to detect, but an image that can be clearly identified as a scratch was obtained. These scratches were brighter than other normal areas.

[Reference example 1]
The arrangement of Example 1 was performed, the first illumination was extinguished, and the same member was observed with only the second illumination. An example of imaging is shown in FIG. Example 1 and the line camera 31 captured images under the same conditions, but the image was dark overall and the S/N ratio was low. rice field.

[Reference example 2]
The arrangement of Example 1 was carried out, the second illumination was extinguished, and the same member was observed with only the first illumination. An example of imaging is shown in FIG. Example 1 and the line camera 31 captured images under the same conditions, but the overall image was darker than that of Reference Example 1, and the S/N ratio was low. became difficult to detect.

[Reference example 3]
Using the second illumination and the line camera used in Example 1, the second illumination was arranged at a second angle θ2 of 70 degrees, and the same member was observed. The observation was made without using the first illumination. An imaging example is shown in FIG.
In this member, oil adhered on the defects observed in Example 1, and the oil itself was imaged due to diffuse reflection of the oil, etc., and the defects on the surface of the member could not be identified.

INDUSTRIAL APPLICABILITY The present invention can be used to inspect defects such as members to which oil may adhere, and is industrially useful.

REFERENCE SIGNS LIST 100 defect inspection device 101 first optical system 102, 102B second optical system 11 first illumination 21, 21B second illumination 31 line camera 4 member 411, 412 irradiation site 413 inspection site 42 axis 51 fixing means 52 Rotation Means 60 Image Detection Section 71 Image Analysis Section 72 Discrimination Section 80 Display Section 90 Memory

Claims (5)

A defect inspection method for a surface of a member that is a columnar member to which oil adheres,
A first illumination that is a line illumination that illuminates the member toward the axis in the height direction of the member, and the member from an angle different from the first illumination toward the axis in the height direction of the member. An irradiation step of irradiating with a second lighting that is a line lighting that irradiates the
an imaging step of imaging the member irradiated in the irradiation step with a line camera;
A first axis formed by an axis along which the line camera images images toward the axis in the height direction of the member, and an axis along which the first illumination illuminates the member toward the axis in the height direction of the member. irradiate linearly along the height direction of the member at an angle (θ1) of 5 to 15 degrees,
A second angle (θ2 ) is irradiated linearly along the height direction of the member at an angle of 20 to 40 degrees. When the axis along which the line camera images the inspection site is viewed in the horizontal direction, the angle formed by the line camera imaging axis and the irradiation axis of the second illumination is from 0 to 60 degrees. 2. The defect inspection method according to claim 1, wherein: 3. The defect inspection method according to claim 1, further comprising a step of rotating the member by rotating means for rotating the member in the circumferential direction. Having an image analysis unit for image analysis of the image captured by the line camera,
4. The defect inspection method according to any one of claims 1 to 3 , further comprising the step of capturing an image of the peripheral surface of the member by capturing an image while rotating the member with the line camera. 5. The method according to any one of claims 1 to 4 , further comprising a step of comparing the luminance of the image picked up by said line camera with a luminance threshold value for judging the presence or absence of a defect in said member, and judging the presence or absence of a defect by a judging section. The defect inspection method described above.

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