JP5589304B2 - Surface inspection apparatus and surface inspection method - Google Patents

Description

  The present invention relates to a surface inspection apparatus and a surface inspection method for detecting the presence or absence of defects on the surface of an inspection object by irradiating a light beam.

  In recent years, electronic devices such as mobile phones and personal computers have become widespread, and improvement in design is also emphasized for these products. Therefore, in order to improve the design of the appearance of products, the casings of those products may be subjected to mirror finishing or polishing.

  Mirror surface processing and glazing processing are generally performed by applying paint or plating on the surface of a casing made of a molded product such as metal or plastic. In this case, irregularities may occur on the surface of the housing after mirror finishing or polishing, due to irregularities on the surface of the molded product or adhesion of foreign matter.

  Even if such a defect is as small as about several μm in size, the defect appears remarkably depending on the illumination environment, which causes the appearance to be greatly impaired. Therefore, in the product manufacturing process, an appearance inspection is performed in order to find defects that impair the appearance of the housing (inspection object).

  As one of the appearance inspection methods, there is a method of measuring the state of regular reflection (specular reflection) on the surface of the inspection object by scanning the surface of the inspection object while irradiating a light beam. In this method, a light receiving element is installed in a direction in which the light beam is regularly reflected, and the intensity of the light beam regularly reflected on the surface of the inspection object is detected by the light receiving element. If there is a defect on the surface of the inspection object, the light beam is diffusely reflected, so that the intensity of the light beam reaching the light receiving element is reduced. Therefore, the presence or absence of a surface defect can be determined by detecting a decrease in the output of the light receiving element.

JP-A-4-194653 JP-A-5-332944 JP-A-10-31110 JP 2007-121291 A

  In the above-described method, the presence or absence of a defect cannot be efficiently inspected in the case of an inspection object having a plurality of surfaces with different inclination angles. That is, in such an inspection object, the direction in which the light beam is specularly reflected is different for each surface having a different inclination angle. Cannot be determined by For this reason, it is necessary to inspect by scanning a plurality of times while changing the incident angle of the light beam for each surface, and the inspection takes time.

  Therefore, an object of the present invention is to provide a surface inspection apparatus and a surface inspection method that can quickly detect the presence or absence of a defect even when the inspection object has a plurality of surfaces with different inclination angles.

According to one aspect, there is a wavelength band with respect to the mounting table on which the inspection target composed of a plurality of surfaces having different inclination angles is mounted and the inspection target mounted on the mounting table. A light source that emits a plurality of different light beams, a light beam converging unit that converges the plurality of light beams regularly reflected by the surface of the inspection object placed on the mounting table, and the inspection object A plurality of light receiving elements arranged at positions corresponding to the inclination angles of the plurality of surfaces constituting the surface of the light receiving the light beam converged by the light beam converging unit, and a light receiving surface side of each of the light receiving elements A plurality of color filters that pass only a light beam of a wavelength band set in advance according to the arranged position, and a light beam for the plurality of light beams irradiated on the surface of the inspection object. In the direction A driving unit for relatively moving the mounting table, and controls the driving unit, and a determining controller the presence or absence of a defect of the surface of the inspection object on the basis of the output of the light receiving element, said plurality The wavelength bands of the light beams that pass through each of the color filters are different from each other and the same as the wavelength bands of the plurality of light beams , and the light beam converging unit is positive on the surface of the inspection object. The plurality of reflected light beams are converged to a position corresponding to an inclination angle of a surface irradiated with the plurality of light beams among the plurality of surfaces constituting the surface of the inspection object, Among the plurality of light receiving elements, a light receiving element arranged at a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams receives the converged light beam, and the driving unit Move the mounting table to Wherein in said plurality of surfaces constituting the surface of the object Ki have changed the face of a plurality of light beam is irradiated, the control unit, the irradiation position of the light beam relative to the surface of the inspection object each Based on the relationship with the output of the light receiving element, the intensity distribution of the light beam regularly reflected on the surface of the inspection object is obtained, and among the plurality of light receiving elements, the surface of the surface irradiated with the plurality of light beams is obtained. A light receiving element arranged at a position corresponding to an inclination angle receives the converged light beam not including light passing through a color filter arranged on the light receiving surface side of the light receiving element among the plurality of color filters. Then, if there is a portion lower than a preset threshold in the intensity distribution of the light beam regularly reflected on the surface of the inspection object, it is determined that the surface of the inspection object has a defect, Furthermore, the control unit Of the plurality of light receiving elements, a first light receiving element disposed at a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams is the first of the plurality of color filters. A plurality of second light receiving elements that receive the converged light beam including light passing through a first color filter disposed on a light receiving surface side of the light receiving element and that are different from the first light receiving element are the plurality of light receiving elements. And receiving the converged light beam including light passing through the second color filter disposed on the light receiving surface side of the second light receiving element, and simultaneously using two or more light receiving elements. A surface inspection apparatus that determines that the surface of the inspection object is defective when the light beam is received is provided.

  The surface inspection apparatus according to the above aspect irradiates the surface of the inspection object with a plurality of light beams having different wavelength bands emitted from the light source arranged in a line in the moving direction of the inspection object. The plurality of light beams regularly reflected on the surface of the inspection object are converged to a predetermined convergence position by the lens. The convergence position of the light beam varies depending on the inclination angle of the surface of the inspection object. Therefore, a convergence position is determined in advance according to the inclination angle of the surface of the inspection object, and a color filter and a light receiving element are arranged at each convergence position. And after extracting only the light beam of the specific wavelength band which changes for every convergence position with a color filter, the intensity | strength of a light beam is detected with a light receiving element.

  Therefore, even if the surface of the inspection object is composed of a plurality of surfaces having different inclination angles, the regularly reflected light beam is always detected by any one of the light receiving elements, so that all the surfaces can be scanned once. The intensity distribution of specular reflection light can be measured. This speeds up the inspection.

FIG. 1 is a block diagram illustrating a surface inspection apparatus according to an embodiment. Drawing 2 is a mimetic diagram showing the example of composition of the light source of the surface inspection device concerning an embodiment (the 1). FIG. 3 is a schematic diagram illustrating a configuration example (No. 2) of the light source of the surface inspection apparatus according to the embodiment. FIG. 4A is a perspective view showing an example of the inspection object, and FIG. 4B is a view showing the height distribution of the inspection object shown in FIG. FIG. 5 is a diagram showing an optical path of the light beam when the first surface of the inspection object shown in FIG. 4 is scanned. FIGS. 6A to 6D are diagrams showing the optical path of the light beam when the second surface of the inspection object shown in FIG. 4 is scanned in order of time. FIG. 7 is a diagram showing an optical path of a light beam when the third surface of the inspection object shown in FIG. 4 is scanned. FIG. 8 is a diagram (part 1) showing time-dependent changes in the intensity of the output signal, with time on the horizontal axis and the intensity of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. FIG. 9 is a flowchart showing a defect detection process of the surface inspection apparatus according to the embodiment. FIG. 10 is a diagram (No. 1) showing a distribution of the integrated values of the output signals, with the position on the horizontal axis and the integrated values of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. FIGS. 11A to 11D show the optical path reflection of the light beam when the defect F having the surface with the same inclination angle as the third surface exists on the second surface of the inspection object. FIG. FIG. 12 is a diagram (part 2) illustrating a change with time in the intensity of the output signal, with time on the horizontal axis and the intensity of the output signal of the light receiving elements 15R, 15G, and 15B on the vertical axis. FIG. 13 is a diagram (part 2) showing the distribution of the integrated values of the output signals, with the position on the horizontal axis and the integrated values of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. FIG. 14 is a diagram showing a change over time in the integrated value of the output signal, with time on the horizontal axis and the integrated value of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. FIG. 15 is a diagram illustrating an arrangement of light receiving elements and color filters when another example of the inspection object is inspected.

  Hereinafter, embodiments will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a surface inspection apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating a configuration example of a light source of the surface inspection apparatus according to the embodiment. FIG. 3 is a schematic diagram illustrating another configuration example of the light source of the surface inspection apparatus according to the embodiment. 1 and 3, the alternate long and short dash line with the symbol R indicates the optical path of the light beam R, and the two-dot chain line with the symbol G and the broken line with the symbol B indicate the light beam G and the light beam B, respectively. The optical path is shown. In FIG. 1, the X direction corresponds to a direction perpendicular to the paper surface.

  As shown in FIG. 1, the surface inspection apparatus 10 according to the present embodiment includes a light source 11, a half mirror 12, a lens 13 (light beam converging unit), color filters 14R, 14G, 14B, light receiving elements 15R, 15G, 15B, A control device 16, a mounting table 17, and a driving device 18 are provided.

  An inspection object 90 is placed on the mounting table 17. The drive unit 18 moves the mounting table 17 in the X direction and the Y direction based on a signal from the control device 16.

  The light source 11 outputs three light beams, a red light beam R, a green light beam G, and a blue light beam B, based on a signal from the control device 16. The light beams R, G, and B are arranged in a line in the vertical direction (Z direction) at a constant pitch p (for example, about 5 mm).

  For example, as shown in FIG. 2, the light source 11 includes light emitting diodes 21R, 21G, and 21B and collimator lenses 22R, 22G, and 22B. The red light emitted from the light emitting diode 21R becomes a highly parallel light beam R by the collimator lens 22R. Similarly, green light and blue light emitted from the light emitting diode 21G and the light emitting diode 21B become highly parallel light beams G and B by the collimator lenses 22G and 22B.

  In place of the configuration shown in FIG. 2, as shown in FIG. 3, the light source 11 includes a white light source 25, and a prism 26 and a prism 27 that separate the light beam from the white light source 25 for each wavelength band. It is good.

  The half mirror 12 is disposed above the inspection object 90 and reflects the light beams R, G, and B emitted from the light source 11 downward. The light beams R, G, and B reflected by the half mirror 12 are arranged in a line in the order of the light beam R, the light beam G, and the light beam B in the Y direction.

  The lens 13 is disposed above the half mirror 12 and the inspection object 90. The lens 13 is a convex lens having a diameter Dia (for example, about 50 mm), and is disposed at a position away from the surface of the inspection object 90 by an objective distance L (for example, about 70 mm) in the Z direction. The lens 13 converges the light beams R, G, and B regularly reflected on the surface of the inspection object 90 at predetermined convergence positions P1 to P3 corresponding to the angle of the inspection surface.

  The light receiving element 15R, the light receiving element 15G, and the light receiving element 15B are arranged side by side in the Y direction. The distance d between the light receiving elements 15R, 15G, and 15B is set according to the arrangement pitch p of the light beams R, G, B and the angle of the inclined surface of the inspection object 90. These light receiving elements 15R, 15G, and 15B are, for example, photosensors such as phototransistors, photodiodes, or CdS elements, or elements in which these photosensors are arranged in an array. A CCD (Charge Coupled Device) sensor or the like may be used as the light receiving elements 15R, 15G, and 15B.

  The color filters 14R, 14G, and 14B are disposed so as to cover the light receiving surfaces of the light receiving elements 15R, 15G, and 15B, respectively. The color filter 14R transmits only the red light beam R, the color filter 14G transmits only the green light beam G, and the color filter 14B transmits only the blue light beam B.

  Hereinafter, the surface inspection method by the inspection apparatus 10 according to the embodiment will be described by taking the case of inspecting the surface of the inspection object shown in FIG. 4 as an example. 4A is a diagram illustrating an example of the inspection object, and FIG. 4B is a diagram illustrating the height distribution in the Y direction of the inspection object illustrated in FIG. 4A.

  As shown in FIGS. 4A and 4B, the inspection object 90 has a first surface 90a, a second surface 90b, and a third surface 90c arranged in the Y direction. The normal direction i of the first surface 90a is inclined from the Z direction to the Y direction by an inclination angle θ1. The normal direction j of the second surface 90b is the same as the Z direction. Further, the normal direction k of the third surface 90c is inclined by the inclination angle θ2 from the Z direction to the Y direction. Here, it is assumed that the inclination angle θ1 of the first surface 90a is −15 °, and the inclination angle θ2 of the third surface 90b is + 15 °. In addition, as shown in FIG. 4A, it is assumed here that there is a defect E on the second surface 90b.

  First, first to third convergence positions P1, P2, and P3 corresponding to the first to third surfaces 90a, 90b, and 90c of the inspection target 90 are obtained.

  The convergence positions P1, P2, and P3 are different positions according to the inclination angle of the surface of the inspection object 90, respectively. The light beams R, G, and B that are specularly reflected by the second surface 90b whose normal direction j is the same as the Z direction are directly above the irradiation direction of the light beam G in the Z direction as shown in FIG. 13 converges to a position (second convergence position P2) that is away from the focal distance f by 13.

  The light beam regularly reflected by the first surface 90a whose normal line direction i is inclined by θ1 from the Z direction to the Y direction is a position separated from the second convergence position P2 by the distance d1 (the first convergence position). Converged to P1). In addition, the light beams R, G, and B regularly reflected by the third surface 90b whose normal direction k is inclined by θ2 from the Z direction to the Y direction are separated from the second convergence position P2 by the distance d2 in the Y direction. It converges to the position (third convergence position P3).

  Here, the distance d between the convergence position of the light beam specularly reflected by the surface whose normal direction is inclined by θ from the Z direction and the second convergence position P2 can be obtained by the following equation (1). it can. Further, the range of the inclination angle θ that can be inspected at this time is determined by the equation (2).

  For example, the diameter Dia of the lens 13 is 50 mm, the focal length f is 75 mm, the objective distance L is 70 mm, and the pitch p of the light beams R, G, and B is 5 mm. As described above, θ1 is set to −15 ° and θ2 is set to + 15 °. In this case, according to the above-described relational expression, the first convergence position P1 is a position away from the second convergence position P2 by −20.1 mm in the Y direction, and the third convergence position P3 is the second convergence position P2. And 20.1 mm away in the Y direction.

  The first to third convergence positions P1 to P3 may be experimentally obtained by actually irradiating the surface of the inspection object 90 with the light beams R, G, and B.

  As described above, convergence positions are obtained in advance according to the surface of the inspection object 90, and the light receiving elements 15R, 15G, and 15B and the color filters 14R, 14G, and the color filters 14R, 14G, and the convergence positions P1, P2, and P3 as shown in FIG. 14B is arranged.

  Next, the inspection object 90 is moved in the Y direction at a constant speed V (for example, 5 mm / s) while irradiating the inspection object 90 with the light beams R, G, and B.

  FIG. 5 is a diagram showing an optical path of a light beam when scanning the first surface 90a of the inspection object shown in FIG. FIGS. 6A to 6D are diagrams showing the optical path of the light beam when the second surface 90b of the inspection object shown in FIG. FIG. 7 is a diagram showing an optical path of a light beam when scanning the third surface 90c of the inspection object 90 shown in FIG. FIG. 8 is a diagram showing the change over time in the intensity of the output signal, with time on the horizontal axis and the intensity of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. In FIG. 8, B-ch represents the output of the light receiving element 15B, G-ch represents the output of the light receiving element 15G, and R-ch represents the output of the light receiving element 15R.

  As shown in FIG. 5, the light beams R, G, and B emitted from the light source 11 are reflected by the half mirror 12 and applied to the first surface 90a. The light beams R, G, and B regularly reflected by the first surface 90a pass through the half mirror 12, and are refracted by the lens 13 and converged to the first convergence position P1. However, since the color filter 14R disposed at the first convergence position P1 passes only the red light beam R, only the red light beam R is detected by the light receiving element 15R. As a result, as shown in FIG. 8, the output signal of the light receiving element 15R (R-ch) becomes high. On the other hand, since the light beams R, G, and B do not reach the light receiving element 15G (G-ch) and the light receiving element 15B (B-ch), the output signal is in a low state.

  When the time further elapses, the inspection object 90 moves and the light beams R, G, and B irradiate the second surface 90b. The light beams R, G, and B that are regularly reflected by the second surface 90b are converged to the second convergence position P2 by the lens 13 as shown in FIG. However, since the color filter 14G disposed at the second convergence position P2 passes only the green light beam G, only the green light beam G is detected by the light receiving element 15G. As a result, the output signal of the light receiving element 15G (G-ch) becomes high as shown in FIG.

  On the other hand, since the light beams R, G, and B do not reach the light receiving elements 15R and 15B, the output signals of the light receiving elements 15R and 15B are in a low state. However, due to the positional relationship between the light beams R, G, and B, the light beam G is applied to the second surface 90b with a delay of Δt (= p / V; about 1 second) from the light beam R. For this reason, in FIG. 8, the output signal of the light receiving element 15G rises with a delay of Δt (about 1 second) from the fall of the output signal of the light receiving element 15R.

  When the time further elapses, the inspection object 90 moves, and the light beams R, G, and B are sequentially irradiated onto the defect E on the second surface 90b as shown in FIGS. . As shown in FIG. 6C, while the light beam G is irradiated on the defect E, the green light beam G is irregularly reflected and does not reach the second convergence position P2. Therefore, as shown in FIG. 8, a low part occurs in the output signal of the light receiving element 15G (G-ch).

  When the time further elapses, the movement of the inspection object 90 causes the light beams R, G, and B to irradiate the third surface 90c as shown in FIG. The light beams R, G, and B that are regularly reflected by the third surface 90c are converged by the lens 13 to the third convergence position P3. However, since the color filter 14B disposed at the third convergence position P3 passes only the blue light beam B, only the blue light beam B is detected on the light receiving surface of the light receiving element 15B. Thereby, as shown in FIG. 8, the output signal from the light receiving element 15B becomes high.

  On the other hand, since the light beams R, G, and B do not reach the light receiving elements 15R and 15G, the output signals of the light receiving elements 15R and 15G are in a low state. Note that the light beam B is applied to the third surface 90c with a delay of Δt (about 1 second) from the light beam G due to the positional relationship of the light beams R, G, and B. Therefore, in FIG. 8, the output signal of the light receiving element 15B rises with a delay of Δt from the fall of the output signal of the light receiving element 15G.

  FIG. 9 is a flowchart showing a defect detection process of the surface inspection apparatus according to the embodiment.

  Based on the waveforms of the light receiving elements 15R, 15G, and 15B, the control device 16 detects the presence or absence of a defect on the surface of the inspection object in the procedure shown in FIG.

  First, the distribution of the intensity of the output signal of each light receiving element 15R, 15G, 15B corresponding to the position on the surface of the inspection object 90 is obtained from the waveform of each light receiving element 15R, 15G, 15B shown in FIG. 8 (step S1). .

  Since the light beams R, G, and B are separated from each other by the pitch p in the Y direction, the light beam G is irradiated to the same position as the light beam R with a delay of time Δt (= pitch p ÷ scanning speed V). Further, the light beam B is irradiated to the same position as the light beam R with a delay of time 2Δt. Therefore, in order to remove the difference in the position direction of the light beams R, G, and B, a correction process for shifting the waveform of the light receiving element 15G shown in FIG. 8 by −Δt in the time axis direction is performed. Further, correction processing is performed to shift the waveform of the light receiving element 15B by −2Δt in the time axis direction. Thereafter, by converting the time axis t into the position Y, the distribution of the intensity of the output signal of each light receiving element 15R, 15G, 15B corresponding to the position Y on the inspection object 90 is obtained.

  Next, the intensity distribution of the output signals of the light receiving elements 15R, 15G, and 15B is integrated to obtain the intensity distribution of the regular reflection light on the surface of the inspection object 90 (step S2).

  FIG. 10 is a diagram showing the distribution of the integrated value of the output signal (the intensity of the specularly reflected light), with the position on the horizontal axis and the integrated value of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis. . For example, the distribution of the integrated value of the output signal (intensity of specular reflection light) as shown in FIG. 10 is obtained by performing the processing of step S1 and step S2 based on the waveform shown in FIG.

  Next, it is examined whether or not there is a portion with a low integrated value (intensity of specular reflection light) of the output signal of the portion corresponding to the inspection object 90. That is, as shown in FIG. 10, a first threshold value (dark threshold value) is set, and it is checked whether or not there is a portion below the first threshold value in the integrated waveform of the portion corresponding to the inspection object 90 (step S3). Note that the first threshold value is set to a value lower than the integrated value of the output signal in a state where only one of the light receiving element 15R, the light receiving element 15G, and the light receiving element 15B is detecting the light beam. If there is a portion below the first threshold in the portion corresponding to the defect E as in the integrated waveform shown in FIG. 10, it is determined in step S3 that the surface of the inspection object 90 has a defect.

  By the way, there is a possibility that a detection omission may occur depending on the shape of the defect only by the detection operation in steps S1 to S3 described above.

  FIGS. 11A to 11D show the optical path reflection of the light beam when the defect F having the surface with the same inclination angle as the third surface exists on the second surface of the inspection object. FIG.

  For example, as shown in FIGS. 11A to 11D, a surface having the same inclination angle as the inclination angle of the other surface (third surface 90 c) is formed on the second surface 90 b of the inspection object 90. Consider a case where there is a defect F having. When the defects F are sequentially irradiated with the light beams R, G, and B, the light beams R, G, and B that are regularly reflected by the defect F are sequentially third as shown in FIGS. The convergence position P3 is reached.

  Then, as shown in FIG. 11C, when the defect F is irradiated with the light beam B, the blue light beam B is formed at the third convergence position P3 even though the second surface 90b is scanned. Reach. At this time, the blue light beam B transmitted through the color filter 14B is detected by the light receiving element 15B. Therefore, as shown in FIG. 12, a portion where the output signal of the light receiving element 15B (B-ch) is high appears in the portion corresponding to the second surface 90b.

  FIG. 13 is a diagram showing a distribution of the integrated values of the output signals, with the position on the horizontal axis and the integrated values of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis.

  When the processing described in steps S1 and S2 described above is performed on the waveform shown in FIG. 12, a distribution of integrated values of output signals as shown in FIG. 13 is obtained. As shown in FIG. 13, the decrease in the output signal of the light receiving element 15G corresponding to the defect F is canceled by the increase in the output signal of the light receiving element 15B corresponding to the defect F. Therefore, although the defect F exists in the first integrated waveform, the integrated value of the output signal (the intensity of the specular reflection light) does not show a portion below the dark threshold, and the defect is overlooked in step S3.

  Therefore, as shown in FIG. 11C, the defect F is detected by examining whether or not a state in which the light beam is simultaneously detected by two or more light receiving elements has occurred.

  That is, if no defect is detected in step S3, the process proceeds to step S4 as shown in FIG. 9, and the waveforms indicating the temporal changes in the output signals of the light receiving elements 15R, 15G, and 15B are integrated as they are.

  FIG. 14 is a diagram showing a change over time in the integrated value of the output signal, with time on the horizontal axis and the integrated value of the output signals of the light receiving elements 15R, 15G, and 15B on the vertical axis.

  For example, when the process of step S4 is performed on the waveform shown in FIG. 12, the waveform shown in FIG. 14 is obtained.

  Next, a second threshold value (bright threshold value) is set for the integrated waveform obtained in step S4, and it is checked whether or not there is a portion exceeding the second threshold value in the second integrated waveform (step S5, FIG. 9). Note that the second threshold value is set to a value higher than the integrated value in a state in which the light beam is detected by only one of the light receiving elements 15R, 15G, and 15B. As shown in FIG. 14, when a portion exceeding the second threshold is detected, it is determined in step S5 that the surface of the inspection object 90 has a defect.

  On the other hand, if a portion exceeding the second threshold is not detected in the integrated waveform obtained in step S4, it is determined in step S5 that there is no defect on the surface of the inspection object 90, and the result is shown in FIG. A series of processing ends.

  As described above, according to the surface inspection apparatus 10 and the surface inspection method using the surface inspection apparatus 10, the inspection target 90 having a plurality of surfaces with different inclination angles is inspected on a plurality of surfaces in one scan. Therefore, the inspection can be performed efficiently.

(Other embodiments)
In the above description, the example in which the convex inspection object 90 shown in FIG. 4 is measured has been described, but the surface inspection apparatus 10 can inspect other inspection objects. For example, as shown in FIG. 15, even a concave inspection object 91 having a first surface 91a, a second surface 91b, and a third surface 91c can be inspected. In this case, as shown in FIG. 15, the light receiving element 15R and the color filter 14R are arranged at the first convergence position P1 (right side) corresponding to the first surface 91a, and the second surface corresponding to the second surface 91b. The light receiving element 15G and the color filter 14G are arranged at the convergence position P2 (center). Further, the light receiving element 15B and the color filter 14B may be arranged at the third convergence position P3 (left side) corresponding to the third surface 91c.

  Further, the number of surfaces of the inspection object 90 is not limited to three, and may have two surfaces or four or more surfaces with different inclination angles. In this case, the number of light beams emitted from the light source 11 is at least equal to or greater than the number of the surfaces of the inspection object 90, and light beams having different wavelength bands are converged at the convergence positions corresponding to the respective surfaces. A color filter to be transmitted and a plurality of light receiving elements may be disposed.

  In the above description, as the simplest example, the first to third convergence positions P1, P2, and P3 are described as being arranged in a line in the Y direction. However, the surface inspection apparatus 10 according to the embodiment is limited to this. Is not to be done. For example, when the tilt angle of the surface of the inspection object is also tilted in the X direction, the convergence position appears at a position shifted further in the X direction, but if a light receiving element and a color filter are appropriately disposed at the convergence position. The presence or absence of defects on the surface of the inspection object can be detected by the same procedure.

  Further, the surface inspection apparatus 10 irradiates the inspection object 90 with the light beams R, G, and B from vertically above (Z direction) through the half mirror, but is not limited thereto. The light beams R, G, and B need only be arranged in a line in the Y direction. For example, the light beams R, G, and B are directly applied to the inspection object 90 from the light source 11 that is disposed obliquely above the inspection object 90. It may be irradiated.

  Furthermore, in the surface inspection apparatus 10, means for converging a plurality of light beams regularly reflected on the surface of the inspection object 90 (light beam converging unit) is not limited to the lens 13, and a concave mirror or the like is used, for example. May be.

  DESCRIPTION OF SYMBOLS 10 ... Surface inspection apparatus, 11 ... Light source, 12 ... Half mirror, 13 ... Lens, 14R, 14G, 14B ... Color filter, 15R, 15G, 15B ... Light receiving element, 16 ... Control device, 17 ... Mounting stand, 21R, 21G , 21B ... light emitting diode, 22R, 22G, 22B ... collimator lens, 25 ... white light source, 26, 27 ... prism, 90, 91 ... inspection object, 90a, 91a ... first surface, 90b, 91b ... second Surface, 90c, 91c ... third surface, P1 ... first convergence position, P2 ... second convergence position, P3 ... third convergence position, R, G, B ... light beams.

Claims (3)

A mounting table on which an inspection object composed of a plurality of surfaces with different inclination angles is mounted;
A light source that emits a plurality of light beams having different wavelength bands with respect to the inspection object mounted on the mounting table;
A light beam converging unit that converges the plurality of light beams specularly reflected on the surface of the inspection object placed on the mounting table,
A plurality of light receiving elements that are arranged at positions corresponding to inclination angles of the plurality of surfaces constituting the surface of the inspection object and receive the light beam converged by the light beam converging unit;
A plurality of color filters that are disposed on each light receiving surface side of the light receiving element, and allow only a light beam in a wavelength band set in advance according to the disposed position;
A drive unit that relatively moves the mounting table in a direction in which light beams are aligned with respect to the plurality of light beams irradiated on the surface of the inspection object;
A control unit that controls the driving unit and determines the presence or absence of defects on the surface of the inspection object based on the output of the light receiving element;
Have
The wavelength bands of the light beams transmitted by each of the plurality of color filters are different from each other, and are the same as the wavelength bands of each of the plurality of light beams,
The light beam converging unit irradiates the plurality of light beams regularly reflected on the surface of the inspection object with the plurality of light beams among the plurality of surfaces constituting the surface of the inspection object. Converge to a position corresponding to the tilt angle of the surface
Among the plurality of light receiving elements, a light receiving element disposed at a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams receives the converged light beam,
The driving unit moves the placing table, Ki are changing the face of the light beam is irradiated in the plurality of in the plurality of surfaces constituting the surface of the inspection object,
The control unit obtains the intensity distribution of the light beam regularly reflected on the surface of the inspection object based on the relationship between the irradiation position of the light beam on the surface of the inspection object and the output of each light receiving element, Among the plurality of light receiving elements, a light receiving element arranged at a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams is a light receiving surface side of the light receiving element of the plurality of color filters. Receiving the converged light beam that does not include light passing through the color filter disposed on the surface of the inspection object and lowering the intensity distribution of the light beam specularly reflected on the surface of the inspection object lower than a preset threshold value Is present, it is determined that the surface of the inspection object has a defect,
Further, the control unit includes a first light receiving element arranged at a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams among the plurality of light receiving elements. And receiving the converged light beam including light passing through the first color filter disposed on the light receiving surface side of the first light receiving element, and a second different from the first light receiving element. The light receiving element receives the converged light beam including the light passing through the second color filter disposed on the light receiving surface side of the second light receiving element among the plurality of color filters, and simultaneously A surface inspection apparatus , wherein when the light beam is received by two or more light receiving elements, the surface of the inspection object is determined to be defective .   The surface inspection apparatus according to claim 1, wherein the plurality of light beams emitted from the light source are emitted in a line. A light source that irradiates a plurality of light beams having different wavelength bands onto an inspection object having a plurality of surfaces with different inclination angles, and converges the plurality of light beams that are regularly reflected by the inspection object. A light beam converging unit, and a plurality of light receiving elements arranged at positions corresponding to inclination angles of the plurality of surfaces constituting the surface of the inspection object, and receiving the light beam converged by the light beam converging unit; A surface inspection method using a surface inspection apparatus that is disposed on each light receiving surface side of the light receiving element and has a plurality of color filters that pass light beams in a wavelength band set in advance according to the disposed positions. There,
The wavelength bands of the light beams transmitted by each of the plurality of color filters are different from each other, and are the same as the wavelength bands of each of the plurality of light beams,
The inspection object is irradiated with the plurality of light beams emitted from the light source, and the plurality of light beams regularly reflected on the surface of the inspection object are converted into the inspection object by the light beam converging unit. Of the plurality of surfaces constituting the surface of the plurality of light beams are converged to a position corresponding to an inclination angle of the surface irradiated with the plurality of light beams, and the plurality of light beams are irradiated among the plurality of light receiving elements. The light receiving element arranged at a position corresponding to the inclination angle of the surface receives the converged light beam,
In the plurality of planes constituting the surface of the inspection object, the inspection object is moved relative to the plurality of light beams irradiated on the inspection object in a direction in which the light beams are arranged. By changing the surface irradiated with the plurality of light beams, the output of the plurality of light receiving elements is measured,
When measuring defects on the surface of the inspection object based on the outputs of the plurality of light receiving elements, based on the relationship between the irradiation position of the light beam on the surface of the inspection object and the outputs of the light receiving elements The intensity distribution of the light beam regularly reflected on the surface of the inspection object is obtained, and the light receiving element is disposed at a position corresponding to the inclination angle of the surface irradiated with the plurality of light beams among the plurality of light receiving elements. A light receiving element receives the converged light beam that does not include light passing through a color filter disposed on the light receiving surface side of the light receiving element among the plurality of color filters, and receives light on the surface of the inspection object. When there is a portion lower than a preset threshold in the intensity distribution of the regularly reflected light beam, it is determined that there is a defect on the surface of the inspection object, and among the plurality of light receiving elements, Multiple A first light receiving element disposed at a position corresponding to an inclination angle of the surface irradiated with the light beam is disposed on the light receiving surface side of the first light receiving element of the plurality of color filters. A second light receiving element that receives the converged light beam including light passing through the color filter and is different from the first light receiving element is the second light receiving element of the plurality of color filters. When the converged light beam including light passing through the second color filter disposed on the light receiving surface side of the light is received and simultaneously received by two or more of the light receiving elements, the inspection object A surface inspection method for determining that a surface of an object has a defect .

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