JP6951439B2 - Surface inspection method, surface inspection equipment and product manufacturing method - Google Patents

Description

The present invention relates to a surface inspection method, a surface inspection apparatus, and a method for manufacturing a product.

As a method for automatically detecting minute irregularities on the surface, a method of inspecting irregularities on the surface of a subject by a magic mirror principle is known. Patent Document 1 discloses a method of irradiating a traveling flat steel sheet surface with convergent light and projecting the light reflected by the steel sheet surface onto a screen to make uneven defects manifest as a light-dark pattern on the screen. ing. In this document, it is described that when the angle of incidence on the steel sheet is θ and the wavelength of the light from the light source is λ, unevenness can be manifested by setting cos θ / λ to a predetermined value or less. Further, Patent Document 1 describes that the steel plate is wound around a roll and the portion wound around the roll is measured to avoid the influence of the pass line fluctuation of the traveling steel plate.

Japanese Patent Application Laid-Open No. 2002-139447

In the method described in Patent Document 1 in which the portion wound around the roll of the steel sheet is irradiated with the convergent light, the detection performance can be maintained constant unless the convergence point of the convergent light is substantially aligned with the outer circumference of the roll. Can not. Although Patent Document 1 does not describe the magnification of the optical image projected on the screen, when the roll diameter changes, the magnification of the reflected light changes as the roll curvature changes. Therefore, even in this case as well. , The detection performance cannot be maintained constant.

According to the first aspect of the present invention, in the surface inspection method, a sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample has a predetermined width and a predetermined thickness. A part of the irradiation light having a sill is irradiated, the reflected light reflected on the convex surface is projected onto the screen to form an optical image, and the irradiation light excluding a part of the irradiation light is projected into the convex shape. The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light, and the surface state of the sample is inspected . When irradiating a part of the sample, the incident angle of the irradiation light on the surface of the sample is adjusted according to the radius of the sample, and the optical image formed on the screen is enlarged with respect to the samples having different radii. With a constant magnification, a part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the sample and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge. The reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position .
According to the second aspect of the present invention, in the surface inspection method, a sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample has a predetermined width and a predetermined thickness. A part of the irradiation light having a sill is irradiated, the reflected light reflected by the convex surface is projected onto the screen to form an optical image, and the irradiation light excluding a part of the irradiation light is projected into the convex shape. The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light, and the surface state of the sample is inspected. When irradiating a part, δ, where R is the radius of the sample, θ is the angle of incidence of the irradiation light on the surface of the sample, and δ is the distance between the optical axis of the irradiation light and the ridgeline of the sample. = R (1-cosθ), and a part of the irradiation light is specified to be separated by a predetermined length in the thickness direction from the position of one side edge and the one side edge of the irradiated portion of the sample. The screen is irradiated toward a region including a position, and the reflected light is projected onto the screen including the inspection point by the reflected light reflected at the specific position.
According to the third aspect of the present invention, in the surface inspection method, a sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample has a predetermined width and a predetermined thickness. A part of the irradiation light having a sill is irradiated, the reflected light reflected by the convex surface is projected onto a screen to form an optical image, and the optical image projected on the screen is read by a line sensor camera. The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light, and the surface of the sample is based on the reflected light intensity distribution of the inspection portion of the optical image specified by the reference light. The state is inspected, and when the sample is rotated, the radius of the sample is R, the magnification in the circumferential direction of the sample on the screen is M, and the pixels of the line sensor camera on the screen. When the dimension is c, the scan rate of the line sensor camera is f, and the rotation speed of the sample is N, the sample is rotated under the condition of satisfying N ≦ c · f (2πR · M), and the irradiation light is emitted. A part of is irradiated toward a region including one side edge of the irradiated portion of the sample and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge, and the screen is provided with the specific portion. The reflected light is projected including the inspection point due to the reflected light reflected at the position.
According to the fourth aspect of the present invention, the surface inspection apparatus is a surface inspection device for irradiating the convex surface of a sample having a circular cross-sectional outer peripheral shape and a convex surface with a predetermined width and a predetermined thickness. The irradiation unit that irradiates a part of the irradiation light and irradiates the irradiation light excluding a part of the irradiation light as a reference light that passes through the convex surface, and the sample are held while rotating around the central axis. A sample holding unit, a screen that forms an optical image based on the reflected light reflected from the convex surface of the sample, an inspection light detection unit that detects the optical image formed on the screen, and the inspection light detection unit. The irradiation unit includes a processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection portion specified by the reference light of the optical image detected in the above, and the irradiation unit corresponds to the radius of the sample. The irradiation light is applied to the sample so that the incident angle of the irradiation light on the surface of the sample is adjusted so that the magnification of the optical image formed on the screen is constant for the samples having different radii. The irradiated portion includes a region of a part of the irradiated light from the position of one side edge of the irradiated portion of the sample to a specific position separated by a predetermined length in the thickness direction. Irradiating in the tangential direction with respect to the one side edge, the screen forms the optical image including the reflected light reflected at the specific position .
According to a fifth aspect of the present invention, the surface inspection apparatus is a surface inspection device for irradiating light having a predetermined width and a predetermined thickness on the convex surface of a sample having a circular cross-sectional outer peripheral shape and a convex surface. The irradiation unit that irradiates a part of the irradiation light and irradiates the irradiation light excluding a part of the irradiation light as a reference light that passes through the convex surface, and the sample are held while rotating around the central axis. A sample holding unit, a screen that forms an optical image based on the reflected light reflected from the convex surface of the sample, an inspection light detection unit that detects the optical image formed on the screen, and the inspection light detection unit. The irradiation unit includes a processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection portion specified by the reference light of the optical image detected in the above, and the irradiation unit has a radius of the sample R. When the angle of incidence of the irradiation light on the surface of the sample is θ and the distance between the optical axis of the irradiation light and the ridgeline of the sample is δ, the relationship is δ = R (1-cosθ). The sample is irradiated with a part of the irradiation light, and the irradiation unit is a specific position in which a part of the irradiation light is separated from the position of one side edge of the irradiated portion of the sample by a predetermined length in the thickness direction. The screen includes the reflected light reflected at the specific position to form the optical image.
According to the sixth aspect of the present invention, the surface inspection apparatus is a surface inspection device for irradiating the convex surface of a sample having a circular cross-sectional outer peripheral shape and a convex surface with a predetermined width and a predetermined thickness. The irradiation unit that irradiates a part of the irradiation light and irradiates the irradiation light excluding a part of the irradiation light as a reference light that passes through the convex surface, and the sample are held while rotating around the central axis. A sample holding unit, a screen that forms an optical image based on the reflected light reflected from the convex surface of the sample, and an inspection light detecting unit that reads and detects the optical image formed on the screen with a line sensor camera. The sample holding unit includes a processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection portion specified by the reference light of the optical image detected by the inspection light detecting unit. The radius of the sample is R, the magnification in the circumferential direction of the sample on the screen is M, the pixel size of the line sensor camera on the screen is c, the scan rate of the line sensor camera is f, and the sample. When the rotation speed of the sample is N, the sample is rotated under the condition that N ≦ c · f (2πRM · M) is satisfied, and the irradiation unit uses a part of the irradiation light as the irradiated portion of the sample. The screen includes the region from the position of one side edge to a specific position separated by a predetermined length in the thickness direction, irradiates the light in the tangential direction with respect to the one side edge, and the screen reflects the reflected light at the specific position. To form the optical image.
According to a seventh aspect of the present invention, in the method for manufacturing a product having a circular outer peripheral shape and a convex surface, the convex surface is processed and the product is rotated about a central axis while rotating the product. The processed convex surface is irradiated with a part of the irradiation light having a predetermined width and a predetermined thickness, and the reflected light reflected by the convex surface is projected onto the screen to form an optical image. Then, the irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light, and the sample is based on the reflected light intensity distribution of the inspection portion of the optical image specified by the reference light. and inspecting the surface state, based on the surface condition of the products examined, to determine the quality of the product, to transfer the products on the basis of the determination result to the next step, a part of the irradiation light on the convex surface When irradiating, the incident angle of the irradiation light on the convex surface is adjusted according to the radius of the product, and the magnification of the optical image formed on the screen is constant for the products having different radii. Then, a part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge, and the screen. Is projected with the reflected light including the inspection portion due to the reflected light reflected at the specific position .
According to an eighth aspect of the present invention, in the method for manufacturing a product having a circular outer peripheral shape and a convex surface, the convex surface is processed and the product is rotated about a central axis while rotating the product. The processed convex surface is irradiated with a part of the irradiation light having a predetermined width and a predetermined thickness, and the reflected light reflected by the convex surface is projected onto the screen to form an optical image. Then, the irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light, and the sample is based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light. The surface condition is inspected, the quality of the product is determined based on the surface condition of the inspected product, the product is moved to the next step based on the determination result, and a part of the irradiation light is irradiated on the convex surface. When the radius of the sample is R, the angle of incidence of the irradiation light on the surface of the sample is θ, and the distance between the optical axis of the irradiation light and the ridgeline of the sample is δ, δ = R (1). -Cosθ), and a part of the irradiation light is a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge. The reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position.
According to the ninth aspect of the present invention, in the method for manufacturing a product having a circular outer peripheral shape and a convex surface, the convex surface is processed and the product is rotated about a central axis while rotating the product. The processed convex surface is irradiated with a part of the irradiation light having a predetermined width and a predetermined thickness, and the reflected light reflected by the convex surface is projected onto the screen to form an optical image. Then, the optical image projected on the screen is read by a line sensor camera, and the irradiation light excluding a part of the irradiation light is passed through the convex surface to be a reference light, and is specified by the reference light. The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection portion of the optical image, the quality of the product is determined based on the surface condition of the inspected product, and the product is subjected to the next step based on the determination result. When rotating the sample, the radius of the sample is R, the magnification of the sample in the circumferential direction on the screen is M, the pixel size of the line sensor camera on the screen is c, and the line. When the scan rate of the sensor camera is f and the rotation speed of the sample is N, the sample is rotated under the condition of satisfying N ≦ c · f (2πRM · M), and a part of the irradiation light is the said. The light is emitted toward a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge, and the screen reflects the reflection reflected at the specific position. The reflected light is projected including the inspection portion by light.

According to the present invention, it is possible to maintain a constant detection performance even if the curvature of the convex surface of the sample differs to some extent.

The plan view which shows the structure of the 1st Embodiment of the surface defect inspection apparatus of this invention. FIG. 5 is a side view of the surface defect inspection apparatus shown in FIG. An enlarged view for explaining an optical image in a state where the surface of a sample to be inspected is irradiated with irradiation light. A plan view of the observation position of the optical image on the screen as viewed from the laser oscillator side. It is a plan view of an optical image acquired by a line sensor camera, (a) is a case where the radius of a sample is 11 mm, and (b) is a case where a radius of a sample is 14 mm. The figure which contrasts the optical image and the inspection condition of the sample of a different radius. The characteristic diagram which shows the relationship of the angle θ-magnification with respect to a specific position P of a sample from the Y axis. It is a figure concerning the 2nd Embodiment of this invention, and is the figure which shows the optical image and the inspection condition of the sample of a different radius when the magnification is constant (20 times) in comparison. It is a plan view of the optical image acquired by the 2nd Embodiment of this invention, (a) is the case of a sample radius R = 11 mm, (b) is the case of a sample radius R = 14 mm. The side view which shows the structure of the 3rd Embodiment of the surface defect inspection apparatus of this invention. The figure which shows the relationship between the illumination area and the observation area of a sample in 3rd Embodiment. It is a plan view of the optical image detected by the two line sensor cameras shown in FIG. 10, (a) is an optical image detected by the line sensor camera 107, and (b) is an optical image detected by the line sensor camera 120. A plan view of the screen side as seen from the light source side, showing a fourth embodiment of the present invention. The plan view which shows the structure of the whole surface defect inspection apparatus of 4th Embodiment of this invention. FIG. 4 is a perspective view of the photodiode and mask illustrated in FIG. It is a figure which shows the intensity distribution of the irradiation light. FIG. The side view which shows the structure of the 5th Embodiment of the surface defect inspection apparatus of this invention. The side view which shows the structure of the modification of the 5th Embodiment of this invention. FIG. 6 is a configuration diagram of a surface inspection system according to the present invention, showing a sixth embodiment of the present invention. The side view which shows the structure of 7th Embodiment of the surface defect inspection apparatus of this invention. The figure for demonstrating the principle of this invention which shows the state which the optical image formed by the reflected light reflected on the surface of a cylindrical sample is magnified and projected on the screen. The figure which shows the irradiation area on the sample illustrated in FIG. 21. FIG. 21 is a characteristic diagram showing the relationship between the angle θ from the Y axis and the magnification M with respect to the specific position P. The flowchart which shows the flow of the process which applied the surface defect inspection apparatus of this invention to the manufacturing process of a piston rod.

According to the present invention, it is possible to maintain a constant detection performance.

The principle of achieving the above object will be described.
FIG. 21 is a diagram showing a state in which an optical image formed by reflected light reflected on the surface of a cylindrical sample is magnified and projected on a screen, and FIG. 22 is a diagram showing a state in which the sample shown in FIG. 21 is projected. It is a figure which shows the upper irradiation area.
The sample 150 to be inspected is a member having a central axis O and having a circular cross-sectional shape, that is, a columnar or cylindrical member. FIG. 21 is a view of the sample 150 cut along a plane orthogonal to the axial direction. Sample 150 has a vertex A on the Y-axis.
In the following description, the X direction, the Y direction, and the Z direction are as shown in the drawings. The Y direction and the Z direction are orthogonal to each other, and the X direction is orthogonal to the Y direction and the Z direction. The Y-axis is located on a straight line connecting the central axis of the sample 150 and the apex A.

The sample 150 is irradiated with a band-shaped irradiation light 151 having a width (length in the X direction) W × a thickness (length in the Y direction) t1. The thickness t1 of the irradiation light 151 is smaller than the radius R of the sample 150. The optical axis 151a of the irradiation light 151 is parallel to the XZ plane. The irradiation light 151 is irradiated in a range of thickness t1 from above the apex A of the sample 150 in the Y direction to the illumination incident point B on the outer peripheral surface of the sample 150. That is, the irradiation light 151 includes a light ray that becomes a contact point with respect to the apex A of the sample 150. This light ray is substantially parallel to the optical axis 151a of the irradiation light 151. Therefore, the irradiation light 151 is irradiated from the tangential direction with respect to the apex A of the sample 150. The optical axis 151a of the irradiation light 151 is located at a point P on the outer peripheral surface of the sample 150 between the apex A of the sample 150 and the illumination incident point B in the Y direction.

On the opposite side of the sample 150 to the side irradiated with the irradiation light 151, the screen 152 is arranged at a position separated by L from the central axis O of the sample 150. The screen 152 is arranged parallel to the XY plane.
A part of the irradiation light 151 irradiates the arc portion AB on the outer peripheral surface of the sample 150. Further, the remaining part of the irradiation light 151 above the apex A of the sample 150 passes through the outer peripheral surface of the sample 150 as the reference light and is directly irradiated to the screen 152 to form a reference image. Assuming that the point where the light beam in contact with the apex A is projected on the screen 152 is S0, the apex A of the sample 150 and the point S0 projected on the screen 152 have the same height in the Y direction. The point S0 on the screen 152 is defined as the reference position. Therefore, all the irradiation light 151 below the reference image position S0 irradiates the arc portion AB on the outer peripheral surface of the sample 150 in a band shape having a width W. In FIG. 22, the irradiation region 153 irradiated to the arc portion AB on the outer peripheral surface of the sample 150 is hatched with diagonal lines. The irradiation light 151 is emitted from an irradiation light source (not shown) toward the sample 150 and the screen 152 via the cylindrical lens 160.

In FIG. 21, the angle of the point P of the sample 150 with respect to the Y axis is defined as θ. The point P of the sample 150 is defined as a specific position. As described above, the position of the optical axis 151a of the irradiation light 151 coincides with the specific position P. The incident angle and the reflection angle of the irradiation light 151 at the specific position P are both u1. The light beam reflected at the specific position P reaches the point S1 on the screen 152. Assuming that the elevation angle of the reflected light from the specific position P is φ1, the height h1 from the reference position S0 to the point S1 on the screen 152 can be obtained by the equation (1).
h1 = tan (φ1) · (L + R · sinθ) -R (1-cosθ) ... (1)
Here, φ1 = 180-2 · u1 and u1 = 90-θ. Therefore, φ1 = 2θ. The thickness t2 of the irradiation light 151 directly applied to the screen 152 is t1 / 2-R (1-cosθ).

Further, at the point Q on the arc portion AB moved from the specific position P by a minute angle, the incident angle and the reflection angle of the irradiation light 151 are both u2, and the light ray reflected at the point Q is at the point S2 on the screen 152. To reach. Assuming that the elevation angle of the reflected light from the point Q is φ2, the height h2 from the reference position S0 to the point S2 on the screen 152 can be obtained by the equation (2).
h2 = tan (φ2) ・ (L + R ・ sin (θ + α)) −R (1-cos (θ + α)) …… (2)
Here, φ2 = 180-2 · u2 and u2 = 90− (θ + α). Therefore, φ2 = 2 (θ + α). Note that α is a central angle with respect to the arc portion PQ.
Similarly, the light beam reflected at the illumination incident point B on the outer circumference of the sample 150 reaches the point S3 on the screen 152. Therefore, the irradiation light radiated on the arc portion AB is projected in the range of points S0 to S3 on the screen 152. In the present invention, the so-called magic mirror principle is used to manifest the uneven portion on the outer peripheral surface of the sample 150 as a shadow of the reflected light projected on the screen 152.

Details will be described later as an embodiment, but the height h1 from the reference position S0 of the point S1 at which the reflected light at the specific position P of the sample 150 is projected onto the screen 152, which is calculated by the equation (1), is shown in FIG. As shown in the above, when the radius R is 11 mm, it is 7.4 mm, and when the radius R is 14 mm, it is 7.42 mm. That is, the difference in h1 when the radii R are 11 mm and 14 mm is only 0.02 mm. This value is smaller than the pixel size c (for example, about 55 μm) of one pixel of the line sensor camera 107 (see FIG. 2) on the screen 152. Therefore, even if the radii R are different to some extent, the optical image projected on the point S1 on the screen 152 can be observed without adjusting the set position (set height) of the specific position P of the sample 150. Is possible.

Next, the magnification of the minute region (arc portion PQ) on the sample 150 is calculated. If the arc portion PQ is set as d, the magnification M in the circumferential direction on the screen 152 can be obtained by the equation (3).
M = (h2-h1) / d …… (3)
h1 and h2 are obtained from the formulas 1 (1) and (2), respectively. The closer the incident angle of the irradiation light 151 to the specific position P is to 90 °, the higher the defect detection sensitivity. Therefore, assuming that θ is inspected under the condition of approximately 5 ° or less, it can be treated as R (1-cos θ) ≈ 0, which is the second term of the equation (1). Further, if L >> R is considered, it can be approximated as (L + R · sin (θ + α)) ≈ L. Therefore, Eq. (3) can be simplified and interpreted as Eq. (4).
M = L (tan (φ2) -tan (φ1)) / d …… (4)

As described above, φ1 = 2θ and φ2 = 2 (θ + α). Further, α = 360 · d / 2πR. Therefore, if the dimension of the arc portion PQ treated as a minute region, that is, d is constant, it can be seen that the enlargement magnification M increases as θ or L increases. That is, under conditions where L is constant, when the optical image on the sample 150 (or the optical image of the defect if there is a defect) is projected onto the screen 152, the height on the screen 152 (position in the Y direction) determines. The magnification is different.

FIG. 23 is a characteristic diagram showing the relationship between the angle θ from the Y axis and the magnification M with respect to the specific position P. In FIG. 23, for each case of sample radius R = 8 mm (○ mark), R = 11 mm (□ mark), and R = 15 mm (△ mark), d = 0.01 mm and L = 50 mm from the formula (3). The result of calculating the correlation between θ and the magnification M is shown. As shown in FIG. 23, the magnification M increases as the angle θ of the specific position P in the sample 150 from the Y axis increases (corresponding to a decrease in the illumination incident angle u1 at the specific position P). It can be read from the equation (1) that h1 increases as θ increases.

Comparing the three types of the sample 150 having a radius R of 8 mm, 11 mm, and 15 mm with reference to FIG. 23, the smaller the radius R, the larger the magnification M on the screen 152. Further, although the numerical value is not displayed in FIG. 23, the magnification M when the illumination incident angle u1 at the specific position P is 85 ° (θ = 5 °) is 13.16 times when R = 8 mm. , 9.65 times when R = 11 mm, and 6.67 times when R = 15 mm. The position of the point S1 from which each magnification factor M is obtained on the screen 152 can be calculated from the equation (1), h1 = 8.91 mm when R = 8 mm, h1 = 8.94 mm when R = 11 mm, R. = 15 mm h1 = 8.99 mm.

From FIG. 23, it is possible to further obtain the conditions for observing the outer peripheral surface of the sample 150 having a different diameter at the same magnification M. For example, θ for observing the outer peripheral surface magnified 20 times is 17.6 ° when R = 8 mm, 22.3 ° when R = 11 mm, and 25.7 ° when R = 15 mm. By substituting these into the equation (1), the height h1 which is each observation position on the screen 152 can be obtained. When R = 8 mm, h1 = 36.60 mm, when R = 11 mm, h1 = 52.60 mm, and when R = 15 mm, h1 = 69.30 mm.
As described above, the radius R of the sample 150, the distance L from the sample 150 to the screen 152, the angle θ with respect to the specific position P, the position S1 of the light rays reflected from the specific position P on the screen 152, and the observation magnification M at the point S1. The correlation can be obtained accurately. Therefore, although the details will be described later, as shown in FIG. 8, when the radius R of the sample 150 is different, the illumination incident angle of the irradiation light 151 on the surface of the sample 150 depends on the size of the radius R of the sample 150. By adjusting u1, the magnification M of the optical image formed on the screen 152 can be made constant. That is, it is possible to maintain a constant detection accuracy even if the radius R of the sample is different to some extent.

− First Embodiment −
The first embodiment of the present invention will be described with reference to FIGS. 1 to 6.
FIG. 1 is a plan view showing the configuration of the first embodiment of the surface defect inspection device of the present invention, and FIG. 2 is a side view of the surface defect inspection device shown in FIG.
The sample 100 to be inspected is, for example, a piston rod used for a shock absorber. The springs and shock absorbers are incorporated into the vehicle body as suspension strut assemblies. The piston rod is a cylindrical structural component that seals the inside of a highly airtight cylinder with a cylindrical sliding surface, and the presence of several um of unevenness on the surface causes oil leakage in the suspension system. Therefore, the roundness and cylindricity are controlled on the order of micrometers, and the arithmetic mean roughness (Ra) of the surface is 0.05 um or less. The piston rod is a cylindrical part made of low carbon steel such as S25C, and is subjected to a quenching and forming process, and then surface-treated to make the surface flat, and then put into the assembly process. The piston rod, which is the sample (hereinafter, simply referred to as “sample”) 100 to be inspected, is generally formed to have a diameter of about 22 mm and a total length of about 250 mm. Connection portions 100a and 100b for mechanical connection are formed at both ends of the sample 100. The connection portions 100a and 100b at both ends are not subject to inspection.

The surface defect inspection device 1 includes a laser oscillator 104, a Powell lens 105, a cylindrical lens 106, rollers 101a, 101b, a line sensor camera 107, a TV camera lens 108, and a screen 102 that irradiate the sample 100 with laser light (irradiation light). I have.
The sample 100 is mounted across the rollers 101a and 101b. The rollers 101a and 101b have the same diameter, and are arranged at the same height position in the Y direction and separated from each other in the Z direction in a state where the axis is parallel to the X axis. The sample 100 is mounted on the roller 101a and the roller 101b so that the axis is arranged on the center line of the boundary between the roller 101a and the roller 101b. The roller 101a is connected to the motor 103. The roller 101b can rotate freely with respect to the axis. By rotationally driving the motor 103, the roller 101a rotates, and the sample 100 and the roller 101b rotate. That is, by controlling the rotation of the motor 103, the rotation of the sample 100 can be controlled at an arbitrary speed.
Although not shown, the rollers 101a and 101b are mounted on a moving stage so that they can be integrally moved in the vertical direction (Y direction).

The laser oscillator (illumination light source) 104 outputs, for example, a parallel beam (sometimes referred to as “irradiation light”) 10 having a wavelength of 670 nm and a diameter of 2 mm. The output of the laser oscillator 104 is, for example, about 100 mW. The parallel beam 10 output from the laser oscillator 104 is fan-shaped only in the XZ plane by the Powell lens 105. The Powell lens 105 is a cylindrical lens having a rounded ridge line, and is also called a laser line generator. It is often used in applications where the parallel beam 10 output from the laser oscillator 104 is extended into a linear shape with a uniform intensity distribution. In this embodiment, the Powell lens 105 exemplifies a parallel beam 10 having a diameter of 2 mm from a laser oscillator 104 extending to a full angle of 30 °. The laser oscillator 104 is a single mode laser, the intensity distribution of the output beam is Gaussian distribution, referred to as 1 / e ² diameter and beam diameter I following. That is, the beam diameter is the width at the intensity when the intensity drops ^{to 1 / e 2 (13.6%) from the peak intensity value.}

As shown in FIG. 1, the cylindrical lens 106 has a curvature only in the XZ plane, has the function of a convex lens in the horizontal direction, and does not have the function of a lens in the vertical direction. The parallel beam 10 emitted from the laser oscillator 104 is formed into a parallel beam 10 having a width (length in the X direction) Wx thickness (length in the Y direction) t1 by a cylindrical lens 106. For example, by using a cylindrical lens 106 with a focal length of 400 mm and adjusting the distance between the Powell lens 105 and the cylindrical lens 106 to approximately 400 mm, a parallel beam 10 having a width W = 200 mm and a thickness t1 = 2 mm is formed. Will be done. The parallel beam 10 formed by the cylindrical lens 106 irradiates the outer peripheral surface of the sample 100 in a band shape. In FIG. 1, the irradiation region 110 of the irradiation light irradiated on the outer peripheral surface of the sample 100 via the cylindrical lens 106 is shown by oblique hatching. The irradiation light is reflected on the outer peripheral surface of the sample 100 and projected onto the screen 102. The reflected light reflected on the outer peripheral surface of the sample 100 is enlarged on the curved surface of the outer peripheral surface of the sample 100 and projected onto the screen 102.

The screen 102 is arranged on the side of the sample 100 opposite to the laser oscillator 104 side, away from the sample 100. The optical image formed by the reflected light magnified and projected on the screen 102 is read by the line sensor camera 107 via the TV camera lens 108 and observed. The TV camera lens 108 and the line sensor camera 107 are arranged coaxially, and the laser oscillator 104, the Powell lens 105, and the cylindrical lens 106 are arranged at an elevation angle β with respect to an optical surface in which the linear lens 106 is linearly arranged. As the material of the screen 102, plain paper that hardly transmits laser light and acts as a diffuser can be used. Further, in the present embodiment, the elevation angle β of the line sensor camera 107 is set to 30 °.

FIG. 3 is an enlarged view for explaining an optical image in a state where the surface of the sample to be inspected is irradiated with irradiation light.
The positional relationship between the field of view of the line sensor camera 107 on the screen 102 and the reflected light from the surface of the sample 100 will be described with reference to FIG.
In the present embodiment, the illumination incident angle u1 to the specific position P on the sample 100 is set to 87 °. Therefore, θ in FIG. 3 is 3 °. As described above, the rollers 101a and 101b on which the sample 100 is mounted can be moved in the vertical direction by a moving stage (not shown). Based on a predetermined inspection recipe, the sample 100 is moved in the vertical direction by a moving stage, and the top apex A (one side edge) of the sample 100 is moved to the height of the optical axis 10a of the parallel beam 10 having a thickness of t1. ) Match the heights exactly. From this state, the sample 100 is raised in the Y direction so that the optical axis 10a of the parallel beam 10 coincides with the specific position P. Assuming that the amount of movement of the sample 100, in other words, the height from the specific position P to the apex A is δ, δ = R (1-cosθ) in FIG. Since the diameter of the sample 100 is 22 mm, and therefore the radius R = 11 mm and θ = 3 °, δ = 0.015 mm.

Here, the thickness t2 of the irradiation light 10 that is directly applied to the screen 102 without irradiating the sample 100 can be obtained by t1 / 2-δ. Since t1 = 2 mm, t2 = 0.985 mm. Let v be the angle from the Y axis with respect to the illumination incident point B where the light beam on the lowermost surface of the parallel beam 10 having a thickness of t1 is applied to the outer peripheral surface of the sample 100, and cos (v) = (R− (t1 / 2 + δ)). / R. From this relational expression, the angle v is 24.8 °.
Assuming that the distance L from the central axis O of the sample 100 to the screen 102 is 70 mm, the height h3 when the light beam reflected at the illumination incident point B reaches the point S3 on the screen 102 is φ1 of the equation (1). Can be obtained by replacing with v, and h3 = 86.66 mm. Further, since θ = 3 °, when the light ray reflected at the specific position P reaches the point S1 on the screen 102, h1 = 7.40 mm is obtained by the equation (1). When the magnification M in the circumferential direction of the surface of the sample 100 in S1 is calculated by the equation (3), M = 13.03.

FIG. 4 is a plan view of the observation position of the optical image on the screen as viewed from the laser oscillator side.
The dimensions of the screen 102 are, for example, 280 mm × 150 mm. The luminous flux reflected on the surface of the sample 100 is projected onto the projection region 12 having a width W = 200 mm × height h3 = 86.66 mm indicated by a two-dot chain line. However, the projection region 12 includes a direct illumination range 11 as a reference image formed by the reference light of the irradiation light 10 that does not irradiate the sample 100. That is, among the parallel beams 10 having a thickness of t1, the luminous flux having a thickness of t2 as the reference light in the region above the apex A of the sample 100 is projected onto the direct illumination range 11 of the screen 102 to form a reference image. The field of view position 109 of the line sensor camera 107 is adjusted to the height of h1 with the point S0 on the screen 102 as a reference position. In this embodiment, h1 = 7.40 mm.

The line sensor camera 107 has 4096 pixels, and the element size c of one pixel is a square shape of 5.5 um. This is magnified 10 times by the TV camera lens 108 and arranged in a conjugate relationship with the screen 102. The element size c of one pixel of the line sensor camera 107 on the screen 102 is 55 um. From these conditions, the field of view length C of the line sensor camera 107 is 225 mm, and includes the width W = 200 mm of the projected region of the reflected light.

The inspection time for observing the entire circumferential direction of the sample 100 by rotating the motor 103 to rotate the sample 100 will be described. When the element size of one pixel of the line sensor camera 107 on the screen 102 is c and the line rate is f, the entire surface of the sample 100 is inspected from the radius R of the sample 100 and the magnification M on the screen 102. The maximum value of the angular velocity N of the rotation for this can be obtained by the equation (5).
N ≦ c ・ f / (2πR ・ M) …… (5)
Here, when c = 0.055 mm, f = 5 kHz, R = 11 mm, and M = 13.03 times, N ≦ 0.3054 rps, and if the reciprocal is taken, the inspection time per sample is about 3.27 sec. / It turns out that it will be a book.

In the above description, the radius R of the sample 100 is 11 mm, but the sample 100 having a diameter other than that can be inspected by the same method. For example, a case where a sample having R = 14 mm is inspected under the condition that the illumination angle of incidence on the surface to be inspected is 87 ° will be described below.
In FIG. 3, δ = R (1-cosθ). The position θ = 3 ° of the specific position P is the same, but since R = 14 mm, δ = 0.019 mm. Here, the thickness t2 of the irradiation light 10 that is directly irradiated to the screen 102 without irradiating the sample 100 can be obtained by t1 / 2-δ. Since t1 = 2 mm, t2 = 0.981 mm. Further, the angle v of the illumination incident point B on the outer circumference of the sample 100 is 22.0 ° from the relational expression of cos (v) = (R− (t1 / 2 + δ)) / R. The distance L from the central axis O of rotation of the sample 100 to the screen 102 is 70 mm. When the light beam reflected at the illumination incident point B reaches the point S3 on the screen 102, it can be obtained by replacing φ1 in the equation (1) with v, and h3 = 71.64 mm. Similarly, since θ = 3 °, when the light ray reflected at the specific position P reaches the point S1 on the screen 102, h1 = 7.42 mm is obtained by the equation (1). When the magnification M of the surface of the sample 100 in S1 is calculated by the equation (3), M = 10.27.

In FIG. 4, the luminous flux reflected on the surface of the sample 100 is projected onto the projection region 12 having a width W = 200 mm × height h3 = 71.64 mm indicated by a two-dot chain line. The field of view position 109 of the line sensor camera 107 is adjusted to the height of h1 with reference to the point S0 on the screen 102. When the radius R of the sample 100 is 14 mm, h1 = 7.42 mm. In the sample 100 having a radius R = 11 mm, h1 = 7.40 mm. The pixel dimension c of the line sensor camera 107 on the screen 102 is 0.055 mm. Therefore, the difference in h1 (0.02 mm) between the samples 100 of the above two examples having different radii R is smaller than the pixel size c of the line sensor camera 107 on the screen 102. Therefore, it is not necessary to change the field of view position 109 of the line sensor camera 107. That is, the surface defect inspection with the radii R = 11 mm and R = 14 mm of the sample 100 can be continuously performed without changing the set position (set height) of the specific position P of the sample 100. Although it depends on the pixel size c of the line sensor camera 107 and the state of the sample 100 to be observed, normally, if the difference in h1 is within the pixel size c of one pixel on the screen 102, the specific position P of the sample 100 P. It is judged that there is no need to change the set position (set height) of.

The inspection time for observing the entire circumferential direction of the sample 100 by driving the motor 103 to rotate the sample 100 will be described. Assuming that the scan rate f of the line sensor camera 107 is 5 kHz, c = 0.055 mm, R = 14 mm, and M = 10.27 times, so N ≦ 0.3044 rps is obtained from the equation (5). Taking this reciprocal, the inspection time per sample is about 3.29 sec / piece. When the radius R of the sample 100 is R = 11 mm, the inspection time is about 3.27 sec / piece, and when the inspection is performed with the scan rate f of the line sensor camera 107 constant, the inspection time varies depending on the diameter of the sample 100. .. However, in practice, both can be regarded as almost the same. The reason why the inspection time is almost the same while the diameter of the sample 100 is increased is due to the difference in the magnification M of the surface of the sample 100 on the screen 102. When R = 11 mm, the magnification is M = 13.03 times, whereas when R = 14 mm, the magnification is as small as M = 10.27 times.

Since the pixel size c of the line sensor camera 107 on the screen 102 is 0.055 mm, the optical image projected on the screen 102 is observed in the circumferential direction of the sample 100 via the screen 102 with a spatial resolution of c / M. Corresponds to that. The observation resolution in the circumferential direction differs depending on the diameter of the sample 100, and the pixel size c of the optical image obtained by the line sensor camera 107 is 4.22 um when R = 11 m and 5.36 um when R = 14 mm. There is.

The above results are shown in FIG. FIG. 6 is a diagram showing the optical images of the objects to be inspected having different radii and the inspection conditions in comparison, and the radii of the sample are 11 mm and 14 mm.

As shown in FIG. 6, the inspection time required for observing the entire outer peripheral surface of the sample 100 is 3.27 sec / piece and the radius R = 14 mm when the radius R = 11 mm of the sample 100. In the case, it is 3.29 sec / piece. However, when the radii R = 11 mm and R = 14 mm of the sample 100, other conditions can be set so that the inspection times for both are the same.
The setting conditions will be described below, but here, an example is given as a case where the inspection time is 3 sec / piece.

When the sample 100 has a radius R = 11 mm, the scan rate f may be obtained as an unknown number in the equation (5) in order to complete the inspection time at 3 sec / piece. Since the reciprocal of the inspection time of 3 sec / piece corresponds to the angular velocity, when N = 1/3 is substituted, the scan rate f = 5.458 kHz. Further, when the sample has a radius R = 14 mm, the scan rate f = 5.475 kHz is obtained by substituting N = 1/3 in the equation (5). Therefore, if the scan rate f of the line sensor camera 107 is 5.458 kHz when the sample 100 has a radius R = 11 mm and 5.475 kHz when the sample 100 has a radius R = 14 mm, whichever is used? In this case as well, the full-scale inspection of the sample 100 can be completed in 3 seconds / piece. By changing the scan rate f of the line sensor camera 107 in this way, it is possible to inspect the surface defects of the samples 100 having different diameters with the same tact.

5A and 5B are schematic plan views of an optical image acquired by a line sensor camera. FIG. 5A shows a sample with a radius of 11 mm, and FIG. 5B shows a sample with a radius of 14 mm. In FIGS. 5A and 5B, the axial direction of the sample 100 is x and the circumferential direction is y.
FIG. 5A shows the reflected light intensity distribution on the screen 102 detected by setting the scan rate f = 5 kHz of the line sensor camera 107 while rotating the sample 100 having a radius R = 11 mm once at 0.3054 rps. Is. The inspection time in this case is 3.27 sec / piece. In the x direction, there is no change in magnification due to the curvature of the sample 100. Therefore, the line sensor camera 107 pixel dimension c on the screen 102 is 0.055 mm, and a range of 200 mm, which is the same as the width W of the irradiation light 10, is detected. The number of pixels in the x direction is 200/0.055 = 3636 pixels. The y direction is the unfolded length of the sample 100 in the circumferential direction, and a range of 69.1 mm has been detected. In the y direction, the magnification M changes depending on the curvature of the sample 100. The pixel dimension c of the line sensor camera 107 is 4.22 um as described above. The number of pixels in the y direction is 69.1 / 0.00422 = 16374 pixels.

FIG. 5B shows the reflected light intensity distribution on the screen 102 detected by setting the scan rate f = 5 kHz of the line sensor camera 107 while rotating the sample 100 having a radius R = 14 mm once at 0.3044 rps. .. The inspection time is 3.29 sec / piece. The number of pixels in the x direction is 3636 pixels as in FIG. 5A. The y direction is the unfolded length of the sample 100 in the circumferential direction, and a range of 88.0 mm has been detected. The pixel dimension c in the y direction is 5.36 um as described above. The number of pixels in the y direction is 88.0 / 0.00536 = 16418 pixels.

In these detection optical images, unevenness defects on the surface of the sample 100 are manifested as bright spots and black spots by the magic mirror principle. The image 51 shown in FIG. 5A and the image 54 shown in FIG. 5B are both black spots and correspond to convex defects on the surface of the sample 100. However, since dust and the like adhering to the surface of the sample 100 also become apparent as black spots, it is preferable to clean the surface of the sample 100 before the inspection. The image 52 shown in FIG. 5A and the images 53 and 55 shown in FIG. 5B are bright spots and correspond to concave defects on the surface of the sample 100. When the surface of the sample 100 is defect-free, no shadow change occurs on the detection optical image.

The defect shapes on the detection optical images shown in FIGS. 5 (a) and 5 (b) are detected as shapes in which the pixel dimensions c in the x and y directions are different and the y direction is stretched with respect to the x direction. Has been done.
As described above, as the diameter of the sample 100 increases, the magnification M in the y direction decreases. Therefore, the length of the outer peripheral surface of the sample 100 differs between FIGS. 5 (a) and 5 (b), but x Images of almost the same size are detected in the axial direction.
The images 51 to 55 shown in FIGS. 5 (a) and 5 (b) are extracted by an image processing device (not shown), and defect information such as defect coordinates, defect dimensions, and defect types is stored in storage means (shown). It is recorded in).

According to the first embodiment, the following effects are obtained.
(1) The sample 100 having a convex surface is irradiated with a part of the irradiation light 10 having a predetermined width W and a predetermined thickness t1, and the reflected light reflected by the convex surface is transmitted to the screen 102. Along with projecting to form an optical image, the irradiation light 10 excluding a part of the irradiation light 10 is used as a reference light to pass through a convex surface and directly irradiate the screen to form a reference image. The surface condition of the sample is inspected based on the reflected light intensity distribution at the inspection location of the specified optical image. According to this configuration, the detection performance can be kept constant even if the radius R of the sample 100 is different to some extent.

(2) A part of the irradiation light applied to the sample 100 includes a peak value of light intensity. Therefore, the irradiation light 10 output from the laser oscillator 104 can be most efficiently utilized in projecting the shadow pattern of the optical image on the screen 102.

(3) The sample 100 is irradiated with irradiation light while rotating around the central axis O, and the entire surface of the sample 100 in the circumferential direction is projected onto the screen 102. Therefore, a small device can inspect the entire outer peripheral surface of the sample 100 projected on the screen 102.

(4) The distance from the central axis O of the sample 100 to the optical axis 10a of the irradiation light 10 is equal to or less than the radius R of the sample 100. Therefore, the reflected light of the sample 100 is projected within substantially the same XY coordinates, and the area of the screen 102 can be reduced.

-Second embodiment-
In the first embodiment, even when the radius R of the sample 100 is different, the position of the height (Y direction) of the optical image corresponding to the specific position P of the sample 100 projected on the screen 102 is substantially set. The surface defect inspection device that can be the same has been described.
In the second embodiment, a surface defect inspection apparatus capable of making the magnification of the optical image projected on the screen 102 the same even when the radii R of the sample 100 are different will be described.
Also in the second embodiment, the configuration of the surface defect inspection device 1 is the same as that of the first embodiment. That is, the surface defect inspection device 1 shown in the first embodiment can also be used as the surface defect inspection device in the second embodiment.
Hereinafter, the details will be described with reference to FIGS. 1 to 4 as an example of the case where the surface defect inspection device 1 inspects the surface defects of the sample 100 having radii R = 11 mm and R = 14 mm.

As described in the first embodiment, FIG. 3 shows an optical image in a state where the surface of the sample to be inspected is irradiated with irradiation light.
FIG. 7 shows a characteristic diagram showing the relationship between the angle θ-magnification from the Y-axis with respect to the specific position P of the sample. The radius R of the sample is 11 mm (marked with a circle) and 14 mm (marked with a cross). The distance L from the central axis O of the sample 100 to the screen 102 is 70 mm, and the length d of the arc portion PQ (see FIG. 21) is 0.01 mm.
First, the magnification M of the outer peripheral surface of the sample 100 on the screen 102 is set. The angle θ for observing the outer peripheral surface of the sample 100 having a different diameter at the same magnification M can be read from FIG. For example, the condition for enlarging the outer peripheral surface of the sample 100 by 20 times is θ = 17.3 ° when the radius R = 11 mm and θ = 21.1 ° when the radius R = 14 mm. Since the illumination incident angle u1 (see FIG. 21) at the specific position P is 90-θ, each illumination incident angle u1 is 72.7 ° when R = 11 mm and 68.9 ° when R = 14 mm, which is a sample. Different conditions are set according to the radius R of 100.

Next, the height of the optical axis 10a of the parallel beam 10 incident on the sample 100 is made to coincide with the specific position P. In FIG. 3, δ = R (1-cosθ). Since the radius R of the sample 100 is 11 mm and θ = 17.3 °, δ = 0.498 mm. Further, the thickness t2 of the irradiation light 10 as the reference light that is directly irradiated to the screen 102 without irradiating the sample 100 can be obtained by t1 / 2-δ. Since t1 = 2 mm, t2 = 0.502 mm.
Further, the angle v of the illumination incident point B on the outer circumference of the sample 100 is 30.2 ° from the relational expression of cos (v) = (R− (t1 / 2 + δ)) / R. Assuming that the distance L from the central axis O of the sample 100 to the screen 102 is 70 mm, when the light beam reflected at the illumination incident point B reaches the point S3 on the screen 102, φ1 in the equation (1) is replaced with v. It can be obtained, and h3 = 129.30 mm. Similarly, since θ = 17.3 °, when the light ray reflected at the specific position P reaches the point S1 on the screen 102, h1 = 50.05 mm is obtained by the equation (1).

In FIG. 4, as described above, the dimensions of the screen 102 are 280 mm × 150 mm. The luminous flux reflected on the surface of the sample 100 is projected onto the projection region 12 having a width W = 200 mm × height h3 = 129.30 mm indicated by a two-dot chain line. However, the projection region 12 includes a direct illumination range 11 as a reference image by the irradiation light 10 that does not irradiate the sample 100. The field of view position 109 of the line sensor camera 107 is adjusted to the height of h1 with reference to the point S0 on the screen 102. In this embodiment, h1 = 50.05 mm as described above.

The case where the radius R = 11 mm of the sample 100 has been described above, but when the radius R = 14 mm, the angle θ = 21.1 °, and the following values are obtained respectively. In FIG. 3, since δ = R (1-cosθ), δ = 0.939 mm. The thickness t2 of the irradiation light 10 that directly irradiates the screen 102 without irradiating the sample 100 can be obtained by t1 / 2-δ. Since t1 = 2 mm, t2 = 0.061 mm. The angle v of the illumination incident point B on the outer circumference of the sample 100 is 30.5 ° from the relational expression of cos (v) = (R− (t1 / 2 + δ)) / R. Assuming that the distance L from the central axis O of the sample 100 to the screen 102 is 70 mm, when the light beam reflected at the illumination incident point B reaches the point S3 on the screen 102, φ1 in the equation (1) is replaced with v. It can be obtained, and h3 = 137.16 mm. Similarly, since θ = 21.1 °, when the light ray reflected at the specific position P reaches the point S1 on the screen 102, h1 = 67.10 mm is obtained by the equation (1).

Therefore, in FIG. 4, the luminous flux reflected on the surface of the sample 100 is projected onto the projection region 12 having a width W = 200 mm × height h3 = 137.16 mm indicated by a two-dot chain line. However, the projection region 12 includes a direct illumination range 11 by the irradiation light 10 that does not irradiate the sample 100. The field of view position 109 of the line sensor camera 107 is adjusted to the height of h1 with reference to the point S0 on the screen 102. In the case of the sample 100 having a radius R = 14 mm, h1 = 67.10 mm as described above.

Next, the relationship between the rotation speed of the sample 100 and the scan rate f of the line sensor camera 107 is obtained. Assuming that the scan rate f of the line sensor camera 107 is 5 kHz, c = 0.055 mm, R = 11 mm, and M = 20 times, so N ≦ 0.1989 rps from the equation (5). Taking this reciprocal, the inspection time per sample with R = 11 mm is about 5.03 sec / piece. When the radius R of the sample 100 is 14 mm, N ≦ 0.1563 rps is obtained from the formula (5). Taking this reciprocal, the inspection time per sample is about 6.40 sec / piece. In this way, when the inspection is performed with the scan rate f of the line sensor camera 107 constant, the inspection time varies depending on the diameter of the sample 100.

Since the pixel size c of the line sensor camera on the screen 102 is 0.055 mm, the optical image projected on the screen 102 is observed in the circumferential direction of the sample 100 via the screen 102 with a spatial resolution of c / M. Corresponds to. In the case of this embodiment, since the magnification M is 20 times regardless of the radius R of the sample 100, the pixel size c in the outer peripheral direction of the sample 100 of the optical image obtained by the line sensor camera 107 is 2.75 um. ..

The above results are shown in FIG. FIG. 8 is a diagram relating to a second embodiment of the present invention, and is a diagram showing optical images and inspection conditions of samples having different radii when the magnification M is constant (20 times). The radii R of the sample 100 are 11 mm and 14 mm, and each numerical value indicates the result of the contents described above. By setting the angle θ from the Y axis (the illumination incident angle at this time is u1) with respect to the specific position P of each sample 100 to the angle shown in FIG. 8, the magnification M is the same (20 times) on the screen 102. ) Optical image can be projected.

9A and 9B are schematic plan views of an optical image obtained by the second embodiment of the present invention, FIG. 9A is a case where the radius R of the sample is R = 11 mm, and FIG. 9B is the radius of the sample. This is the case of R = 14 mm.
Note that FIG. 9 (a) is an inspection result of a sample having the same defect as FIG. 5 (a) and FIG. 9 (b) is an inspection result of FIG. 5 (b). In FIGS. 9A and 9B, the axial direction of the sample 100 is x and the circumferential direction is y.
FIG. 9A is an optical image detected by rotating the sample 100 having a radius R = 11 mm once at 0.1989 rps and setting the scan rate f = 5 kHz of the line sensor camera 107. The inspection time is 5.03 sec / piece. In the x direction, there is no change in magnification due to the curvature of the sample 100. Therefore, the pixel size c is 0.055 mm, and a range of 200 mm, which is the same as the width W of the irradiation light 10, is detected. The number of pixels in the x direction is 200/0.055 = 3636 pixels. The y direction is the unfolded length of the sample 100 in the circumferential direction, and a range of 69.1 mm has been detected. In the y direction, the magnification changes depending on the curvature of the sample 100. The pixel dimension c of the line sensor camera 107 is 2.75 um as described above. The number of pixels in the y direction is 69.1 / 0.00275 = 25127 pixels.

FIG. 9B is an optical image detected by rotating the sample 100 having a radius R = 14 mm once at 0.1563 rps and setting the line rate f = 5 kHz of the line sensor camera 107. The inspection time is 6.40 sec / piece. The number of pixels in the x direction is the same as in FIG. 9A, which is 3636 pixels. The y direction is the unfolded length of the sample 100 in the circumferential direction, and a range of 88.0 mm has been detected. The pixel dimension c in the y direction of the optical image of FIG. 9B is also 2.75 um. The number of pixels in the y direction is 88.0 / 0.00275 = 32000 pixels.

The defect shapes on the detection optical images shown in FIGS. 9 (a) and 9 (b) are detected as shapes in which the pixel dimensions in the x direction and the y direction are different and the y direction is stretched with respect to the x direction. ing. The image size of the detected optical image in the y direction is larger in FIG. 9 (b) than in FIG. 9 (a). The image 51 of FIG. 9A and the image 54 of FIG. 9B are both black spots and correspond to convex defects on the surface of the sample 100. The image 52 of FIG. 9A and the images 53 and 55 of FIG. 9B are bright spots and correspond to concave defects on the surface of the sample 100. The number of pixels in the x direction of the images 51 to 55 detected in FIGS. 9 (a) and 9 (b) is the same as that of FIGS. 5 (a) and 5 (b). However, in the y direction, it is detected in a form stretched from those in FIGS. 5 (a) and 5 (b). In FIGS. 9A and 9B, since the magnification M in the y direction is both 20 times, the magnitude relation of the images 51 to 55 can be directly compared.

The images 51 to 55 shown in FIGS. 9 (a) and 9 (b) are extracted by an image processing device (not shown), and defect information such as defect coordinates, defect dimensions, and defect types is stored in storage means (shown). It is recorded in).
According to the second embodiment, the following effects are obtained.
(1) The cylindrical sample 100 is irradiated with the laser beam (irradiation light) 10 of the sample 100, and the reflected light reflected by the surface of the cylindrical portion of the sample 100 is projected onto the screen 102 to form an optical image. , A surface inspection method for inspecting the surface condition of a sample based on the optical image, wherein the irradiation light 10 includes a region from the position of the apex A of the sample 100 to a specific position P separated by a predetermined length in the thickness direction. It is irradiated in the tangential direction with respect to one side edge, is projected on the screen 102 including the reflected light reflected at the specific position P, and is projected on the screen including the reflected light reflected at the specific position. .. According to this configuration, by adjusting the set position (set height) of the specific position P of the sample 100, the magnification M of the optical image projected on the screen can be made constant, and the radius R of the sample 100 can be made constant. It is possible to maintain a constant detection accuracy even if the values are different to some extent.

-Third embodiment-
A third embodiment of the present invention will be described with reference to FIGS. 10 to 12.
FIG. 10 is a side view showing the configuration of a third embodiment of the surface defect inspection apparatus of the present invention.
The surface defect inspection device 1A of the third embodiment further includes a line sensor camera 120 and a TV camera lens 121 in addition to the surface defect inspection device 1 of the first and second embodiments.
The line sensor camera 120 and the TV camera lens 121 are arranged coaxially, and the outer peripheral surface of the sample 100 is directly observed from an elevation angle of γ with respect to the XZ plane. The elevation angle γ is the optimum angle within the range of 5 ° to 90 °. In this embodiment, the elevation angle γ = 45 ° is illustrated. The elevation angle γ that arranges the line sensor camera 120 and the TV camera lens 121 needs to avoid interference with the line sensor camera 107. The line sensor camera 120 and the TV camera lens 121 have the same specifications as the line sensor camera 107 and the TV camera lens 108, respectively.

FIG. 11 is a diagram showing the relationship between the illumination region and the observation region of the sample in the third embodiment. FIG. 11 is an XZ plan view.
The field of view position 122 of the line sensor camera 120 coincides with the irradiation region 110 of the irradiation light irradiated on the outer peripheral surface of the sample 100 via the cylindrical lens 106. The line sensor camera 120 has 4096 pixels, and the element size c of one pixel is a square shape of 5.5 um. This is magnified 10 times by the TV camera lens 121 and arranged in a conjugate relationship with the surface of the sample 100. The element size c of one pixel of the line sensor camera 120 on the sample 100 is 55 um. From these conditions, the field of view length Ca of the line sensor camera 120 is 225 mm, which includes the width W = 200 mm of the illumination region on the sample 100.

The conditions under which the motor 103 is rotationally driven to rotate the sample 100 and the optical image on the surface of the sample 100 is detected by the line sensor camera 107 will be described. First, conditions for observing the screen 102 with the line sensor camera 107 are set. The angle of incidence of illumination on the surface of the sample 100 is u1 = 87 ° (θ = 3 °), the radius R of the sample 100 is 11 mm, and the distance L from the central axis O of the sample 100 to the screen 102 is L = 70 mm. In this case, the height h1 = 7.40 mm with respect to the point S0 on the screen 102, and by observing the position S1 on the screen 102 at this time with the line sensor camera 107, the sample 100 on the screen 102 It has been described in the first embodiment that the surface magnification M = 13.03 times can be obtained. Further, if the element size c = 0.055 mm of one pixel of the line sensor camera 107 on the screen 102 and the line rate is f = 5 kHz, the maximum value of the angular velocity N of the rod rotation for performing the entire surface inspection of the sample 100 is obtained. Was obtained from the formula (5), and it was also shown that N ≦ 0.3054 rps.

Regarding the scan rate f of the line sensor camera 120, f can be calculated as an unknown variable by the equation (5). However, since the line sensor camera 120 directly observes the outer peripheral surface of the sample 100, it is treated as a magnification of M = 1. In the formula (5), when N = 0.3054 rps, c = 0.055 mm, R = 11 mm, and M = 1, f = 383.8 Hz is obtained. The scan rate f of the line sensor camera 120 is used as 384 Hz. That is, it may be set to 1 / 13.03 of the line rate of the line sensor camera 107.

12A and 12B are schematic plan views of optical images detected by the two line sensor cameras shown in FIG. 10, FIG. 12A is an optical image detected by the line sensor camera 107, and FIG. 12B is a line. It is an optical image detected by the sensor camera 120.
FIG. 12A shows the reflected light intensity distribution on the screen 102 detected by setting the scan rate f of the line sensor camera 107 to the condition of 5 kHz while rotating the sample 100 with R = 11 mm at 0.3054 rps. It is an optical image similar to FIG. 5 (a). However, while the image 51 in FIG. 5 (a) is illustrated as a convex defect, in FIG. 12 (a), the image 58 is shown as dust. The inspection time is 3.27 sec / piece. Let x be the axial direction of the sample 100 and y be the circumferential direction. In the x direction, there is no change in magnification due to the curvature of the sample 100. Therefore, the pixel size c is 0.055 mm, and a range of 200 mm, which is the same as the width W of the irradiation light 10, is detected. The number of pixels in the x direction is 200/0.055 = 3636 pixels. The y direction is the unfolded length in the circumferential direction of the rod, and a range of 69.1 mm has been detected. In the y direction, the pixel dimension c is 0.055 / 13.03 = 4.22um because the magnification M changes depending on the rod curvature. The number of pixels in the y direction is 69.1 / 0.00422 = 16374 pixels.

FIG. 12B is a schematic view of an optical image detected by the line sensor camera 120, and is a scattered light intensity distribution on the surface of the sample 100 detected by setting the scan rate f to the condition of 384 Hz. The inspection time is 3.27 sec / piece as in FIG. 12 (a). The pixel dimensions c in both the x-direction and the y-direction are 0.055 mm. The number of pixels in the x direction is 3636 pixels as in FIG. 12A. The y direction is the unfolded length of the sample 100 in the circumferential direction, and a range of 69.1 mm has been detected. The number of pixels in the y direction is 69.1 / 0.055 = 1256 pixels.

The image 52 in FIG. 12A is a bright spot and corresponds to a concave defect on the surface of the sample 100. In FIG. 12B, which is an optical image detected by the line sensor camera 120, scattered light generated by protrusions on the surface of the sample 100 is manifested as bright spots. 58, 56, 57 are the detected bright spots. In the detection by the line sensor camera 120, the concave defect on the surface of the sample 100 has no detection sensitivity. Therefore, it can be confirmed that the image 52 in FIG. 12A is a concave defect also by the detection image in FIG. 12B.
It is not possible to distinguish whether the image 58 is a defect or dust only from FIG. 12 (a). Both the optical image detected by the line sensor camera 120 and the optical image detected by the line sensor camera 107 detect an optical image having a shape that reflects the shape of defects or dust. As described above, the pixel dimensions c in the x-direction and the y-direction in the detection optical image of FIG. 12B are both 0.055 mm. The image 58 in FIG. 12 (a) and the image 58 in FIG. 12 (b) have the same xy coordinates. From this, it is determined that the image 58 in FIG. 12 (a) and the image 58 in FIG. 12 (b) are the same object. The shape of the image 58 shows the shape of dust such as lint. Therefore, it is determined that the image 58 is not a defect on the surface of the sample 100, but is likely to be dust adhering to the surface.

As described above, the pixel dimensions c in the x-direction and the y-direction in the detection optical image of FIG. 12B are both 0.055 mm. In the case of defect detection by dark field illumination, it has detection sensitivity even for minute defects smaller than the pixel size c. Therefore, in FIG. 12B, images 56 and 57 that are not detected in FIG. 12A are detected. The shapes of the images 56 and 57 in FIG. 12B are close to a perfect circle. Generally, there is no dust that is close to a perfect circle. Therefore, it is judged that the images 56 and 57 shown in FIG. 12B are highly likely to be concave defects on the surface of the sample 100.

The images 58, 52, 56, and 57 shown in FIGS. 12 (a) and 12 (b) are extracted by an image processing means (not shown) and store defect information such as defect coordinates, defect dimensions, and defect types. Recorded in means (not shown).

The surface defect inspection device 1A of the third embodiment has the same effect as the surface defect inspection device 1 of the first and second embodiments.
In addition, according to the surface defect inspection device 1A of the third embodiment, since the optical image of the surface of the sample 100 is observed by two types of observation optical systems having different illumination conditions, the detected optical image is the sample 100. It is also possible to determine that there is a high possibility that the dust adheres to the surface of the sample 100, not due to a minute defect. Therefore, the efficiency of analysis can be improved.

− Fourth Embodiment −
A fourth embodiment of the present invention will be described with reference to FIGS. 13 to 16.
FIG. 13 shows a fourth embodiment of the present invention and is a plan view of the screen side as viewed from the light source side, and FIG. 14 shows the configuration of the entire surface defect inspection apparatus of the fourth embodiment of the present invention. It is a plan view.
The surface defect inspection device 1B of the fourth embodiment is the same as the surface defect inspection device 1 exemplified in the first and second embodiments. However, the mask 142 and the photodiode 140 are arranged behind the screen 130. Further, the screen 130 is provided with openings 131 and 132 at each end in the X direction.
The mask 142 is arranged behind the screen 130 so as to correspond to the openings 131 and 132. The luminous flux above the apex A of the sample 100 of the parallel beam 10 is incident on the photodiode 140 through the opening 132 and the mask 142.

FIG. 15 is a perspective view of the photodiode and mask illustrated in FIG. The mask 142 is made of a metal plate that does not transmit the irradiation light 10. A slit 143 is provided in the center of the mask 142. The opening size of the slit 143 is 1 mm × 8 mm (X direction × Y direction). The mask 142 is arranged close to the light receiving surface 141 of the photodiode 140. A part of the irradiation light 10 that has passed through the opening 132 of the screen 130, that is, a portion having a thickness t2 of the irradiation light 10 passes through the slit 143 of the mask 142 and is received by the photodiode 140. If the sample 100 is not present in the irradiation optical path, the photodiode 140 receives light having a width of 1 mm in the slit 143 and a thickness t1 = 2 mm (X direction × Y direction) of the irradiation light 10. When the sample 100 is arranged on the irradiation light path, the irradiation light 10 is blocked by the sample 100, and the amount of received light is reduced. The amount of light received by the photodiode 140 varies depending on the area of the sample 100 that blocks the irradiation optical path. Utilizing this, the position of the sample 100 that blocks the irradiation light 10 can be detected.

Prior to the inspection of the surface defect, the angle θ with respect to the specific position P is determined from the information of the desired illumination incident angle with respect to the specific position P on the outer peripheral surface of the sample 100. From this angle θ and the radius R of the sample 100, the height δ of the sample 100 with respect to the optical axis 10a of the irradiation light 10 can be obtained as δ = R (1-cos θ). For example, if θ = 17.3 ° and R = 11 mm, then δ = 0.498 mm. Here, if the thickness of the irradiation light 10 is t1 = 2 mm, the thickness of the irradiation light 10 that is directly irradiated to the screen 130 without irradiating the sample 100 is t2 = t1 / 2-δ. It is obtained as t2 = 0.502 mm. The intensity distribution of the illumination light 10 in the YZ plane is a Gaussian distribution, defined as 1 / e ² diameter thick drives out of t1.

In the present embodiment, in order to precisely adjust the angle θ with respect to the specific position P, the radius R, and the angle δ that changes according to the inspection conditions of the thickness t1 of the irradiation light 10, the light amount is detected by the photodiode 140, and the result is Is fed back to the displacement of the moving stage (not shown) of the sample 100.
16A and 16B are diagrams showing the intensity distribution of the irradiation light, FIG. 16A is a characteristic diagram of the distance from the Y-axis and the relative intensity, and FIG. 16B is the distance from the Y-axis and the integrated light amount. It is a characteristic diagram.
FIG. 16A is a relative intensity distribution of the irradiation light 10 having a thickness t1 = 2 mm in the YZ plane. The laser oscillator 104 is a single-mode laser, and the YX plane is not affected by the beam forming action of the Powell lens 105 and the cylindrical lens 106, and the surface of the sample 100 is irradiated with its intensity distribution as it is in the Gaussian distribution. For convenience, it is referred to as a sheet thickness drives out 1 / e ² diameter of the maximum intensity, in fact has a side lobe, the light is irradiated to a range wider than the thickness t1. The Gaussian distribution showing the maximum intensity at the center of the parallel beam 10 can be obtained by the equation (6) as the intensity I (Y) at an arbitrary coordinate Y in the radial direction, where ω is the Gaussian radius.
I (Y) = I (0) · exp (-2Y ² / ω ² ) …… (6)
Here, I (0) is the intensity on the optical axis 10a. FIG. 16A is a relative intensity distribution obtained from the equation (6) with I (0) = 1 and ω = t1 / 2.

When the sample 100 has a radius R = 11 mm, δ = 0.498 mm satisfying the condition of θ = 17.3 °. In FIG. 16A, the position of Y = 0 mm is the optical axis 10a, δ corresponds to the range of Y = 0 to 0.498, and t2 indicates the range of Y = 0.498 to 1. In the present embodiment, if the sample 100 is not present in the irradiation optical path, the entire area of the intensity distribution waveform of FIG. 14a is detected by the photodiode 140. On the other hand, when the sample 100 is present under the condition of δ = 0.498 mm, only the range shown by the diagonal line in FIG. 16A is detected by the photodiode 140.

The ratio of the amount of light incident on the photodiode 140 can be calculated by integrating Eq. (6) to obtain the area ratio. FIG. 16B is the result of integrating the irradiation light amount of the intensity distribution shown in FIG. 16A in the range of Y = -2 mm to +2 mm. It can be seen that when δ = 0.498 mm, about 86.4% of the total amount of light is irradiated on the surface of the sample 100, and the remaining 13.6% is received by the photodiode 140.

Once the illumination angle of incidence on the surface of the sample 100 is determined by the above method, the height δ of the sample 100 is obtained from the inspection conditions of the radius R of the sample 100 and the thickness t1 of the irradiation light 10, and the amount of detected light of the photodiode 140 is determined. By raising the sample 100 while monitoring, the height of the sample 100 can be precisely positioned.

Although FIG. 14 shows the photodiode 140 arranged with respect to the opening 132 of the screen 130, the photodiode 140 and the mask 142 are similarly arranged with respect to the opening 131 in FIG. 13. By adjusting the height δ of the sample 100 using two photodiodes 140 arranged apart from each other in the X direction, the parallelism of the sample 100 rotation axis and the irradiation light 10 in the XY plane is precisely adjusted. be able to.

The surface defect inspection device 1B of the fourth embodiment has the same effect as the surface defect inspection device 1 of the first and second embodiments.
In addition, the height δ from the apex A to the specific position P of the sample 100 can be accurately measured, and the setting of the sample 100 to the specific position P can be easily and quickly performed.

-Fifth Embodiment-
A fifth embodiment of the present invention will be described with reference to FIGS. 17 and 18.
FIG. 17 is a side view showing the configuration of the fifth embodiment of the surface defect inspection device 1 of the present invention.
In the first to fourth embodiments, the irradiation light 10 is a parallel beam, and the radiation angle of the parallel beam, that is, the inclination is not considered.
In the fifth embodiment, the influence of the parallelism of the irradiation luminous flux 20 in the YZ plane will be considered.
FIG. 17 shows how the irradiation light flux 20 emitted from the virtual point F at an angle of full-width η0 irradiates the surface of the sample 100. The XZ plane is treated as a parallel luminous flux as described above.
When the specific position P on the outer circumference of the sample 100 is aligned with the height of the optical axis 20a, the light reflected at the specific position P reaches the point S1 on the screen 102. On the other hand, the illumination incident angle u2a at the point Q on the circumference moved from the specific position P by the angle α is smaller by η1 than when the parallel luminous flux is incident.
When the radius of the sample 100 is R, the angle with respect to the specific position P is θ, the difference in height between the apex A and the specific position P is δ, and the distance from the virtual point F in the XZ plane to the central axis O of the sample 100 is l. , The correlation between these and η1 is as shown in equation (7). Although δ is not shown in FIG. 17, it points to the same position as in FIG.
tan (η1) = (R (1-cos (θ + α))-δ) / (l-R ・ sin (θ + α)) …… (7)

Here, if η0 = 20 mrad, it is obtained by l = 1 / tan (η0 / 2) when the beam thickness is 2 mm on the Y-axis, so l = 100 mm. Further, as in the first embodiment, if R = 11 mm and θ = 3 °, then δ = R (1-cosθ), so δ = 0.015 mm. Further, if the arc portion PQ is set as d and d = 0.01 mm, α = 360 · d / 2πR, so α is calculated as 0.052 °. By substituting these into equation (7), η1 = 6.057 × 10 ^-6 °, that is, 0.106 urad can be obtained.

Therefore, as described above, u2a = 90− (θ + α) −η1 and φ2a = 180-2 · u2a, so φ2a = 6.104012 ° is calculated. ^{This is 0.012 × 10 -3} ° larger than when a parallel luminous flux is incident on the point Q, but it is a small value. When L = 70 mm and φ2a is substituted into the equation (2), h2 = 7.532828 mm is obtained. This is 0.015 um larger than when a parallel luminous flux is incident on the point Q.

As described above, when the point Q on the outer circumference of the sample 100 is irradiated with the divergent light having a full width of 20 mrad, the point S2a on the screen 102 moves to a position 0.015 um higher. However, since the pixel size c of the line sensor camera 107 on the screen 102 is 55 um, its influence can be ignored.

The light beam as the reference light emitted from the virtual point F passes near the apex A and is directly irradiated to the reference position S0a on the screen 102 to form a reference image. Therefore, the angle of η2 is generated for this light ray as well. Tan (η2) = δ / l, and in the case of this embodiment, it is calculated as ^{η2 = 0.15 × 10 -3 °.} Therefore, the reference position S0a on the screen 102 also moves to a higher position by L · tan (η2) = 0.26 um. By changing the distance l between the virtual point F and the apex A, the positions of the point S2a and the reference position S0a on the screen 102 change slightly, but the change in position can be calculated by the above method. When l is changed, the thickness of the irradiation light flux 20 at the apex A on the outer circumference of the sample 100 also changes. However, if the thickness of the irradiation light flux 20 is approximately 1/10 of the diameter of the sample 100, the screen 102 The amount of movement between the upper point S2a and the reference position S0a is negligible. In the fifth embodiment, the luminous flux emitted from the virtual point F includes a light beam that is a tangent to the apex A of the sample 100.

FIG. 18 is a side view showing the configuration of a modified example of the fifth embodiment of the present invention.
FIG. 18 shows a state in which the surface of the sample 100 is irradiated with an irradiation light flux 30 that converges at an angle of full-width η0 from the virtual point F. The XZ plane is treated as a parallel luminous flux as described above.
When the height of the optical axis 30a of the irradiation luminous flux 30 is aligned with the specific position P on the outer circumference of the sample 100, the light reflected at the specific position P reaches the point S1 on the screen 102. On the other hand, the illumination incident angle u2b at the point Q on the circumference moved from the specific position P by the angle α is larger by η1 than when the parallel luminous flux is incident.
When the radius of the sample 100 is R, the angle with respect to the specific position P is θ, the difference in height between the apex A and the specific position P is δ, and the distance from the central axis O of the sample 100 to the virtual point F in the XZ plane is l. , The correlation between these and the η1 is as shown in the equation (8). Although δ is not shown in FIG. 16, it points to the same position as in FIG.
tan (η1) = (R (1-cos (θ + α)) −δ) / (l + R · sin (θ + α)) …… (8)

Here, if η0 = 20 mrad, it is obtained by l = 1 / tan (η0 / 2) when the sheet beam thickness is 2 mm on the Y axis, so l = 100 mm. Further, as in the first embodiment, if R = 11 mm and θ = 3 °, then δ = R (1-cosθ), so δ = 0.015 mm. Further, if the arc portion PQ is set as d and d = 0.01 mm, α = 360 · d / 2πR, so α is calculated as 0.052 °. By substituting these into equation (8), η1 = 0.343 × 10 ^-3 °, that is, 5.986 rad can be obtained.

Therefore, as described above, u2b = 90− (θ + α) + η1 and φ2b = 180-2 · u2b, so φ2b = 6.133 ° is calculated. ^{This is 0.7 × 10 -3} ° smaller than when a parallel luminous flux is incident on the point Q, but it is a slight value. When L = 70 mm and φ2b is substituted into the equation (2), h2 = 7.5319 mm is obtained. This is 0.9um smaller than when a parallel luminous flux is incident on the point Q.

As described above, when the point Q on the circumference of the sample is irradiated with the convergent light having a full width of 20 mrad, the point S2b on the screen 102 moves to a position 0.9 um lower. However, since the pixel size c of the line sensor camera 107 on the screen 102 is 55 um, its influence can be ignored.

The light beam as the reference light emitted from the virtual point F passes in the vicinity of the apex A and is directly irradiated to the point S0b on the screen 102 to form a reference image. Therefore, the angle of η2 is generated for this light ray as well. Tan (η2) = δ / l, which is also calculated as ^{η2 = 0.15 × 10 -3 °.} Therefore, the point S0b on the screen 102 also moves to a position lower by L · tan (η2) = 0.26 um. By changing the distance l between the virtual points F and A, the positions of the points S2b and the reference position S0b on the screen 102 change slightly, but the change in position can be calculated by the above method. When l is changed, the thickness of the irradiation light flux 30 at the apex A on the outer circumference of the sample 100 also changes. However, if the thickness of the irradiation light flux 30 is approximately 1/10 of the diameter of the sample 100, the screen 102 The amount of movement of the positions of the upper points S2b and S0b is negligible. Also in the modified example of the fifth embodiment shown in FIG. 18, the luminous flux converging on the virtual point F includes a light beam that is a tangent to the apex A of the sample 100.

As described above, in the first to fourth embodiments, the irradiation light fluxes 20 and 30 to irradiate the sample 100 do not need to be parallel light fluxes having a total angle of about mrad, which is usually regarded as parallel, and are numbers in full angle. A divergent or converging luminous flux of about 10 mrad or more can be used.
Generally, a laser oscillator having a parallel beam has a full-width of about 5 mrad or less. In the present invention, a laser oscillator having a full width of 20 mrad or more can be adopted. Therefore, it is possible to reduce the cost of the laser device. Further, even if a luminous flux that diverges or converges is used, the height difference δ between the apex A and the specific position P is substantially the same as that of the parallel light beam, so that the adjustment at the time of inspection becomes easy.

-Sixth Embodiment-
FIG. 19 shows a sixth embodiment and is a block diagram of a surface inspection system according to the present invention.
The surface inspection system includes a surface defect inspection device 1C. The surface defect inspection device 1C includes an irradiation light source 171, rollers 101a and 101b, a roller unit 172, a screen 102, a receiver 175, a screen swing mechanism 176, a line sensor camera 107, and a TV camera lens 108.
The irradiation light source 171 includes a laser oscillator 104 (see FIG. 1) and a lens unit that forms a luminous flux emitted from the laser oscillator 104. A part of the irradiation light 10 positioned at a predetermined height is irradiated in a band shape on the arc portion AB including the apex A and the specific position P of the sample 100. The irradiation light 10 applied to the arc portion AB of the sample 100 is reflected by the arc portion AB of the sample 100 and is irradiated to the screen 102. Further, the reference light which is another part of the irradiation light 10, that is, the luminous flux having a thickness t2 above the apex A of the sample 100 is directly irradiated to the screen 102, and a part thereof is a part of the screen. It passes through the opening 132 of 102 (see FIG. 13) and is detected by the receiver 175.

The cylindrical sample 100 to be inspected is mounted on the roller unit 172 by a loader (not shown). The roller unit 172 includes a sensor (not shown) that reads the identification number stamped on the surface of the sample 100. The computer 179 downloads the inspection recipe 181 of the sample 100 from the upper server 182. The inspection recipe 181 includes the manufacturing process of the sample 100, the diameter, and the inspection conditions at the time of surface inspection.

Based on the contents of the inspection recipe 181, the computer 179 adjusts the height of the height adjusting stage 174 so that the irradiation light 10 emitted from the irradiation light source 171 has a desired incident angle with respect to the outer peripheral surface of the sample 100. , Adjust the height of sample 100. At this time, precise height position setting is realized by adjusting the height of the height adjustment stage 174 while sequentially detecting the output of the receiver 175 that changes depending on the height of the sample 100.

By the above procedure, the relative alignment between the irradiation light 10 and the sample 100 is completed. As a result, the irradiation light 10 emitted from the irradiation light source 171 irradiates the arc portion AB (see FIG. 3) of the sample 100 in a band shape from the tangential direction with respect to the apex A of the sample 100. The light reflected by the arc portion AB of the sample 100 is projected to a predetermined position on the screen 102.

The line sensor camera 107 and the TV camera lens 108 are mounted on the camera height adjustment stage 177. The computer 179 adjusts the height of the camera height adjustment stage 177 based on the inspection recipe 181 to adjust the height of the observation view of the line sensor camera 107 on the screen 102.

When the positioning is completed as described above, the motor controller 173 is controlled based on the inspection recipe 181 to rotate the sample 100 once at a constant speed. While rotating the sample 100, the line sensor camera 107 is driven at a predetermined scan rate f to capture an optical image of the reflected light projected on the screen 102.

The image captured by the line sensor camera 107 is captured by the computer 179. As described above, all device operations are controlled by the computer 179 via the device control unit 178. A defect detection algorithm is implemented in the computer 179, and the defect coordinates on the surface of the sample 100 are divided into an axial direction and a circumferential direction and recorded in the storage device 180 by image processing.

When the inspection of the sample 100 is completed, the sample 100 is dispensed from the roller unit 172 with an unloader (not shown). The surface inspection system of the present invention realizes in-line 100% inspection of rods of different diameters. Therefore, if this surface inspection system is applied to each manufacturing process of the rod as a sample, a process monitor that immediately detects a defective part in the manufacturing process can be realized. Further, if the surface inspection system of the present invention is applied to the final visual inspection process, 100% quality assurance of products can be realized.

In this embodiment, since the irradiation light source 171 is a laser light source, a laser speckle is generated on the screen 102. In order to remove this, a screen swing mechanism 176 is provided.

In the above description, the configuration for observing the optical image pattern due to the reflected light reflected on the outer peripheral surface of the screen 102 has been described. However, as described as the third embodiment, if the line sensor camera 120 for directly observing the surface of the sample 100 shown in FIG. 10 is added, is the optical image obtained from the sample 100 due to a defect? It is possible to improve the discriminability of dust. Further, in each of the embodiments described so far, the case where the front surface of the screen 102 is observed by the line sensor cameras 107 and 120 has been illustrated, but the screen 102 is made of a translucent material and the back surface of the screen 102 is observed. Is also good.

-Seventh Embodiment-
FIG. 20 is a side view showing the configuration of a seventh embodiment of the surface defect inspection apparatus of the present invention.
In the first to fifth embodiments, the sample 100 to be inspected is made into a cylindrical member, and is exemplified as surface defect inspection devices 1, 1A to 1C for inspecting defects on the outer peripheral surface thereof. In the seventh embodiment, the surface defect inspection apparatus 1D applied to the inspection of surface defects of sheet-like members such as rolled steel sheets and films will be illustrated.
The surface defect inspection device 1D includes an irradiation light source 171, a transfer roller 200, a screen 102, a line sensor camera 107, and a TV camera lens 108.
The sample 201 to be inspected is a sheet member such as a metal plate. The sheet-shaped sample 201 is run on a production line or an inspection line by a running belt or a moving device (not shown). The sample 201 is wound around a part of the outer peripheral surface of the cylindrical transfer roller 200 and is conveyed so as to change its direction. The portion of the sample 201 wound around the transport roller 200 has an arc shape that follows the shape of the outer peripheral surface of the transport roller 200. The inspection of the outer peripheral surface of the arc portion of the sample 201 is equivalent to the inspection of the outer peripheral surface of the cylindrical sample 100 having a radius R equal to the sum of the radius of the arc portion of the sample 201 and the thickness of the sample 201.

The irradiation light source 171 includes a lens unit that forms a luminous flux emitted from a laser oscillator. The irradiation light 10 emitted from the irradiation light source 171 irradiates the outer peripheral surface of the sample 201 on the transport roller 200. The irradiation light 10 is emitted from the tangential direction of the apex A of the arc portion of the sample 201. The irradiation light 10 irradiates the region including the apex A of the sample 201 to the specific position P of the sample 201 in a band shape. The irradiation light 10 is incident at a specific position P of the sample 201 at an illumination incident angle u3 and is reflected at the same angle u3. The reflected light reflected by the sample 201 is projected onto the screen 102. The optical image of the region including the specific position P of the sample 201 projected on the screen 102 is observed by the line sensor camera 107 and the TV camera lens 108. A part of the irradiation light 10 is not irradiated to the sample 201 as a reference light, but is directly irradiated to the screen 102 to form a reference image.

When the irradiation light 10 is divergent light or convergent light, the distance L1 between the irradiation light source 171 and the central axis O of rotation of the transfer roller 200 is adjusted, and the thickness t1 of the irradiation light 10 on the transfer roller 200 is the optimum condition. Set to. Further, by moving the irradiation light source 171 in the direction parallel to the normal line 202 connecting the central axis O and the apex A, the magnification of the surface of the sample 201 projected on the screen 102 can be adjusted. That is, if the irradiation light source 171 is moved in the direction of the arrow 203 in the drawing, the incident angle u3 of the irradiation light 10 at the specific position P becomes large, and the magnification on the screen 102 becomes small. On the contrary, if the light is moved in the direction of the arrow 204 in the drawing, the incident angle u3 of the irradiation light 10 at the specific position P becomes smaller, and the magnification on the screen 102 becomes larger. The magnification can also be adjusted by changing the distance L2 between the central axis O of the transport roller 200 and the screen 102.

In the production line for transporting the sheet-shaped sample 201, the transport speed fluctuates at the start and end of the inspection, or during the manufacture thereof, and acceleration / deceleration occurs with respect to the target transport speed. In that case, if a rotary encoder (not shown) is connected to the transfer roller 200 and the line rate of the line sensor camera 107 is controlled by using the encoder pulse, the influence of the transfer speed fluctuation can be eliminated.
As described above, the surface defect inspection device 1D can be applied even when observing the surface of the sheet-like member wound around the cylindrical roller, and the same effect as that of the first and second embodiments can be obtained. Play.

FIG. 24 is a flowchart showing a process flow in which the surface defect inspection device of the present invention is applied to the manufacturing process of the piston rod. First, the process of processing the piston rod will be described. The applicable product is not limited to the piston rod, and any product having a convex surface including a curved surface may be used. That is, it can be applied to the first to seventh embodiments. First, a cylindrical material (low carbon steel) having a constant diameter is subjected to quenching treatment 241 in order to increase its surface hardness, and then shape correction treatment 242 is performed to keep the cylindricity of the material constant. Keep within accuracy. After that, the mechanical joints (100a and 100b in FIG. 1) are processed and molded by the both end molding process 243 of the material, the surface of the sample 100 is smoothed by the surface grinding process 244, and the Cr plating layer is formed on the surface by the plating process 246. Is formed.

Here, a part of the piston rod after the surface grinding process 244 is extracted, and the surface is inspected by the surface defect inspection apparatus of the present invention in the inspection step 245 to grasp the occurrence state of the unevenness defect on the surface of the piston rod before plating. (Inspection 1). The defect detection data 245'in the inspection step 245 is recorded and analyzed in the central processing unit 250. For example, the number of defects on the surface of the piston rod tends to gradually increase due to wear or deterioration of the grinding wheel used in the surface grinding process 244, and the replacement of the grinding wheel is promoted.
The piston rod after the plating treatment 246 is subjected to a surface polishing treatment 248, the surface roughness thereof is finished to less than 0.05 um (arithmetic mean roughness), and the piston rod is transferred to the assembly process. Here, a part of the piston rod after the plating treatment 246 is extracted, and the surface is inspected by the surface defect inspection apparatus of the present invention in the inspection step 247 to grasp the occurrence state of the unevenness defect on the surface of the piston rod before polishing (). Inspection 2). The defect detection data 247'in the inspection step 247 is recorded and analyzed in the central processing unit 250. For example, the maintenance of the plating treatment condition is promoted by grasping the tendency that the number of defects on the surface of the piston rod gradually increases due to the fluctuation of the treatment condition (current value and treatment time fluctuation) in the plating treatment 246, deterioration of the plating solution, and the like.

The surface of the piston rod after the surface polishing treatment 248 is inspected by the surface defect inspection apparatus of the present invention in the inspection step 249, and the occurrence state of uneven defects on the surface of the piston rod after polishing is grasped (inspection 3). .. The defect detection data 249'in the inspection step 249 is recorded and analyzed in the central processing unit 250. In the inspection step 249, all the piston rods are inspected to prevent the outflow of defective products to the assembly process.
For example, the same piston rods were inspected in inspection steps 245, 247, 249 and detected in inspection step 249 by integrating their defect detection data 245', 247', 249'in the central processing unit 250. From the coordinate information of the defect, the cause of the defect can be traced back. Alternatively, when the coordinates of the concave defect detected in the inspection step 249 are traced back to the same piston rod, there is a case where there is no defect in the inspection step 245 and 247. In this case, the concave defect is likely to be a dent generated after the surface polishing treatment.
As described above, by applying the surface defect inspection apparatus of the present invention to the manufacturing process of the piston rod, it is possible to detect the process of each processing process or more at an early stage. In addition, by feeding back the defect detection data, there is an effect of suppressing the creation of defective products. As a result, the manufacturing yield of the piston rod is improved.

In the above embodiment, the inspection apparatus and inspection method of the present invention have been described as observing or detecting surface defects of samples 100 and 201. However, the present invention can also be applied to the detection and observation of the state of the surface of the sample and the substance adhering to or formed on the surface of the sample other than the defects on the surface of the samples 100 and 201.

In each of the above embodiments, the cross-sectional shape of the sample 100 is illustrated as a circle. However, the present invention can also be applied when the surface shape of the sample 100 is curved in an elliptical shape or the like.

In each of the above embodiments, the optical image projected on the screen 102 is illustrated as being detected or observed by the line sensor camera 107 and the TV camera lens 108. However, an image sensor may be integrally provided on the screen 102, and the reflected light 2 from the samples 100 and 201 may be read by the image sensor.

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

The disclosure of the next priority basic application is incorporated here as a quotation.
Japanese Patent Application No. 120867, 2017 (filed on June 20, 2017)

1,1A-1D Surface defect inspection device 10,151 Parallel beam (irradiation light)
10a, 20a, 30a, 151a Optical axis 20, 30 Irradiation luminous flux 51-58 Image 100, 201 Sample 102, 130, 152 Screen 104 Laser oscillator (irradiation light source)
107, 120 line sensor camera (photodetector)
108, 121 TV camera lens 140 photodiode (intensity detector)
171 Irradiation light source 172 Roller unit (sample holding part)
178 Device control unit 179 Computer (processing unit)
A vertex (one side edge)
P Specific position u1-u3 Illumination incident angle

Claims (20)

A sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample is irradiated with a part of irradiation light having a predetermined width and a predetermined thickness to form the convex. The reflected light reflected on the surface is projected onto the screen to form an optical image.
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
A surface inspection method for inspecting the surface condition of the sample based on the reflected light intensity distribution of the inspection portion of the optical image specified by the reference light.
When irradiating the sample with a part of the irradiation light, the incident angle of the irradiation light on the surface of the sample is adjusted according to the radius of the sample, and the sample is formed on the screen with respect to the samples having different radii. To keep the magnification of the optical image constant,
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the sample and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A surface inspection method in which the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. A sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample is irradiated with a part of irradiation light having a predetermined width and a predetermined thickness to form the convex. The reflected light reflected on the surface is projected onto the screen to form an optical image.
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
A surface inspection method for inspecting the surface condition of the sample based on the reflected light intensity distribution of the inspection portion of the optical image specified by the reference light.
When irradiating the sample with a part of the irradiation light, the radius of the sample is R, the angle of incidence of the irradiation light on the surface of the sample is θ, and the distance between the optical axis of the irradiation light and the ridgeline of the sample. When is δ, the relationship of δ = R (1-cosθ) is set.
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the sample and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A surface inspection method in which the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. A sample having a circular outer peripheral shape and a convex surface is rotated about a central axis, and the sample is irradiated with a part of irradiation light having a predetermined width and a predetermined thickness to form the convex. The reflected light reflected on the surface is projected onto the screen to form an optical image.
The optical image projected on the screen is read by a line sensor camera and read.
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
A surface inspection method for inspecting the surface condition of the sample based on the reflected light intensity distribution of the inspection portion of the optical image specified by the reference light.
When rotating the sample, the radius of the sample is R, the magnification in the circumferential direction of the sample on the screen is M, the pixel size of the line sensor camera on the screen is c, and the line sensor camera is rotated. When the scan rate is f and the rotation speed of the sample is N, the sample is rotated under the condition that N ≦ c · f (2πR · M) is satisfied.
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the sample and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A surface inspection method in which the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. In the surface inspection method according to any one of claims 1 to 3,
A surface inspection method in which a part of the irradiation light includes a peak portion of light intensity. In the surface inspection method according to claim 4,
A surface inspection method in which the peak portion of the irradiation light is irradiated to the specific position. In the surface inspection method according to any one of claims 1 to 3,
A surface inspection method in which the screen is irradiated with the reference light to form a reference image, and the inspection location of the optical image reflected from the specific position of the sample is specified based on the reference image. In the surface inspection method according to any one of claims 1 to 3,
A surface inspection method in which the distance from the central axis of the sample to the optical axis of the irradiation light is equal to or less than the radius of the sample. In the surface inspection method according to any one of claims 1 to 3,
A surface inspection method in which the sample is a strip-shaped member, and at the time of the inspection, the sample is deformed to form the convex surface. The convex surface of the sample cross-sectional outer periphery shape having it convex surface circular irradiates a portion of the illumination light having a predetermined width and a predetermined thickness, excluding the part of the irradiation light An irradiation unit that irradiates the irradiation light as a reference light that passes through the convex surface, and an irradiation unit.
A sample holding unit that holds the sample while rotating it around the central axis,
A screen that forms an optical image based on the reflected light reflected from the convex surface of the sample.
An inspection light detection unit that detects the optical image formed on the screen, and
A processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection location specified by the reference light of the optical image detected by the inspection light detection unit, and a processing unit.
Equipped with a,
The irradiation unit adjusts the incident angle of the irradiation light on the surface of the sample according to the radius of the sample, and magnifies the optical image formed on the screen with respect to the samples having different radii. The sample is irradiated with a part of the irradiation light so as to be constant.
The irradiation unit includes a region of a part of the irradiation light from the position of one side edge of the irradiated portion of the sample to a specific position separated by a predetermined length in the thickness direction, and is in a tangential direction with respect to the one side edge. Irradiate towards
The screen is a surface inspection device that forms the optical image including the reflected light reflected at the specific position. The convex surface of the sample cross-sectional outer periphery shape having it convex surface circular irradiates a portion of the illumination light having a predetermined width and a predetermined thickness, excluding the part of the irradiation light An irradiation unit that irradiates the irradiation light as a reference light that passes through the convex surface, and an irradiation unit.
A sample holding unit that holds the sample while rotating it around the central axis,
A screen that forms an optical image based on the reflected light reflected from the convex surface of the sample.
An inspection light detection unit that detects the optical image formed on the screen, and
A processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection location specified by the reference light of the optical image detected by the inspection light detection unit, and a processing unit.
Equipped with a,
The irradiation unit has δ = R, where R is the radius of the sample, θ is the angle of incidence of the irradiation light on the surface of the sample, and δ is the distance between the optical axis of the irradiation light and the ridgeline of the sample. The sample is irradiated with a part of the irradiation light so as to have a relationship of (1-cosθ).
The irradiation unit includes a region of a part of the irradiation light from the position of one side edge of the irradiated portion of the sample to a specific position separated by a predetermined length in the thickness direction, and is in a tangential direction with respect to the one side edge. Irradiate towards
The screen is a surface inspection device that forms the optical image including the reflected light reflected at the specific position. The convex surface of the sample cross-sectional outer periphery shape having it convex surface circular irradiates a portion of the illumination light having a predetermined width and a predetermined thickness, excluding the part of the irradiation light An irradiation unit that irradiates the irradiation light as a reference light that passes through the convex surface, and an irradiation unit.
A sample holding unit that holds the sample while rotating it around the central axis,
A screen that forms an optical image based on the reflected light reflected from the convex surface of the sample.
An inspection light detection unit that reads and detects the optical image formed on the screen with a line sensor camera, and
A processing unit that detects the surface state of the sample based on the reflected light intensity distribution of the inspection location specified by the reference light of the optical image detected by the inspection light detection unit, and a processing unit.
Equipped with a,
The sample holding unit has a radius of the sample of R, a magnification of the sample in the circumferential direction on the screen of M, a pixel size of the line sensor camera on the screen of c, and a scan of the line sensor camera. When the rate is f and the rotation speed of the sample is N, the sample is rotated under the condition that N ≦ c · f (2πR · M) is satisfied.
The irradiation unit includes a region of a part of the irradiation light from the position of one side edge of the irradiated portion of the sample to a specific position separated by a predetermined length in the thickness direction, and is in a tangential direction with respect to the one side edge. Irradiate towards
The screen is a surface inspection device that forms the optical image including the reflected light reflected at the specific position. In the surface inspection apparatus according to any one of claims 9 to 11.
The irradiation unit is a surface inspection device that irradiates a part of the irradiation light on the surface of the sample so that a part of the irradiation light includes a peak value of light intensity. In the surface inspection apparatus according to any one of claims 9 to 11.
A reference light detection unit for detecting the reference light is provided.
The processing unit is a surface inspection device that controls the relative positions of the sample and the irradiation unit based on the reference light detected by the reference light detection unit. In the surface inspection apparatus according to any one of claims 9 to 11.
The inspection light detection unit includes a first photodetection unit that detects an optical image of the screen formed by projecting a part of the irradiation light reflected from the surface of the sample.
A surface inspection apparatus comprising a second photodetector for detecting a part of scattered light of the irradiation light irradiated on the surface of the sample. In the surface inspection apparatus according to claim 14,
The processing unit is a surface inspection device that discriminates the surface state based on the scattered light detected by the first photodetector and the optical image detected by the second photodetector. A method for manufacturing a product having a circular outer peripheral shape and a convex surface.
The convex surface is processed and
While rotating the product around the central axis, the processed convex surface was irradiated with a part of irradiation light having a predetermined width and a predetermined thickness and reflected by the convex surface. The reflected light is projected onto the screen to form an optical image,
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light.
Based on the surface condition of the inspected product, the quality of the product is judged.
The product to move to the next step based on the determination result,
When irradiating a part of the irradiation light on the convex surface, the incident angle of the irradiation light on the convex surface is adjusted according to the radius of the product, and the screen is applied to the products having different radii. The magnification of the optical image formed on the
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A method for manufacturing a product, wherein the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. A method for manufacturing a product having a circular outer peripheral shape and a convex surface.
The convex surface is processed and
While rotating the product around the central axis, the processed convex surface was irradiated with a part of irradiation light having a predetermined width and a predetermined thickness and reflected by the convex surface. The reflected light is projected onto the screen to form an optical image,
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light.
Based on the surface condition of the inspected product, the quality of the product is judged.
The product to move to the next step based on the determination result,
When irradiating the convex surface with a part of the irradiation light, the radius of the sample is R, the angle of incidence of the irradiation light on the surface of the sample is θ, the optical axis of the irradiation light and the ridgeline of the sample. When the distance of is δ, the relationship of δ = R (1-cosθ) is set.
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A method for manufacturing a product, wherein the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. A method for manufacturing a product having a circular outer peripheral shape and a convex surface.
The convex surface is processed and
While rotating the product around the central axis, the processed convex surface was irradiated with a part of irradiation light having a predetermined width and a predetermined thickness and reflected by the convex surface. The reflected light is projected onto the screen to form an optical image,
The optical image projected on the screen is read by a line sensor camera and read.
The irradiation light excluding a part of the irradiation light is passed through the convex surface to be used as a reference light.
The surface condition of the sample is inspected based on the reflected light intensity distribution of the inspection point of the optical image specified by the reference light.
Based on the surface condition of the inspected product, the quality of the product is judged.
The product to move to the next step based on the determination result,
When rotating the sample, the radius of the sample is R, the magnification in the circumferential direction of the sample on the screen is M, the pixel size of the line sensor camera on the screen is c, and the line sensor camera is rotated. When the scan rate is f and the rotation speed of the sample is N, the sample is rotated under the condition that N ≦ c · f (2πR · M) is satisfied.
A part of the irradiation light is irradiated toward a region including one side edge of the irradiated portion of the product and a specific position separated by a predetermined length in the thickness direction from the position of the one side edge.
A method for manufacturing a product, wherein the reflected light is projected onto the screen including the inspection portion due to the reflected light reflected at the specific position. In the method for manufacturing a product according to any one of claims 16 to 18.
A method for manufacturing a product, wherein the reference light passes through the convex surface and directly irradiates the screen to form a reference image. In the method for manufacturing a product according to any one of claims 16 to 18.
A method for manufacturing a product, in which a part of the reference light is directly irradiated to an optical sensor for detection.

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