Visual inspection device

Abstract

To provide a visual inspection device that prevents the object to be imaged from being irradiated with untended light and enables capturing of clear images.SOLUTION: Provided is a visual inspection device 1 comprising: a stage 10 on which an object 100 to be imaged is located; an illumination 20 for irradiating the object to be imaged on the stage with illumination light; an imaging unit 30 for receiving reflected light of light irradiated from the illumination and reflected by the object to be imaged on the stage and capturing an image of the object to be imaged; a second polarizing filter 50 for causing illumination light oscillating in a given direction to pass through and located between the object to be imaged on the stage and the illumination; a first polarizing filter 40 for causing reflected light oscillating in a direction different from the illumination light having passed through the second polarizing filter to pass through and located between the object to be imaged on the stage and the imaging unit; and a shield 60 for blocking illumination light not passing through the second polarizing filter from reaching the object to be imaged on the stage and located between the object to be imaged on the stage and the illumination.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a visual inspection apparatus. [Background technology]

[0002] In recent years, with the improvement of information processing speed, high-speed visual inspection of various electronic components has been put into practical use. For example, an illumination light is irradiated onto the inspection object being transported, and images captured by the light reflected from the inspection object are processed to separate good products from those with visual defects.

[0003] In such appearance inspection devices, the pass / fail of the inspection object is determined optically, so improving the quality of the captured image is important, and there is a demand for faster processing speeds and improved reliability to capture highly accurate images.

[0004] For example, Patent Document 1 discloses that by installing a polarizing plate in the optical path of illumination light or reflected light, the occurrence of phenomena that degrade image quality, such as halation, in the captured image is suppressed, thereby improving the accuracy of appearance inspection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-092436 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the measuring device described in Patent Document 1, a polarizing plate is simply placed between the light source and the object to be measured, and depending on the distance between the light source and the polarizing plate and the type of light source, light that does not pass through the polarizing plate may be irradiated onto the object to be measured. If light that does not pass through the polarizing plate is irradiated onto the object to be measured, it will be reflected as noise in the captured image, making it impossible to capture a clear image, which can lead to reduced inspection accuracy.

[0007] The present invention has been made to solve the above problems, and aims to provide an appearance inspection device that prevents unintended light from being irradiated onto the object to be imaged, thereby enabling clear imaging. [Means for solving the problem]

[0008] The appearance inspection device of the present invention is characterized in that it comprises a stage on which an object to be imaged is placed, an illumination that irradiates illumination light onto the object to be imaged on the stage, an imaging unit that receives light irradiated from the illumination and reflected by the object to be imaged on the stage to image the object to be imaged, a first polarizing filter that is arranged between the object to be imaged on the stage and the illumination and transmits illumination light that vibrates in a fixed direction, a second polarizing filter that is arranged between the object to be imaged on the stage and the imaging unit and transmits reflected light that vibrates in a direction different from the illumination light that has passed through the first polarizing filter, and a light shield that is arranged between the object to be imaged on the stage and the illumination and blocks illumination light that does not pass through the first polarizing filter from reaching the object to be imaged on the stage. Effect of the Invention

[0009] According to the present invention, it is possible to provide a visual inspection device that prevents unintended light from being irradiated onto an object to be imaged and enables clear imaging. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of a visual inspection apparatus of the present invention. [Diagram 2] FIG. 2 is a perspective view illustrating a schematic example of a ring illumination. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4]FIG. 4 is a schematic diagram showing an example of an appearance inspection apparatus in which the ring illumination shown in FIGS. 2 and 3 is arranged coaxially with an imaging section. [Diagram 5] FIG. 5 is a schematic diagram of an image of an electronic component having a crack or chip on a ridge line, captured by the visual inspection device of the present invention. [Figure 6] FIG. 6 is a partially enlarged view of FIG. [Figure 7] FIG. 7 is an example of a binarized image obtained by binarizing the image shown in FIG. [Figure 8] FIG. 8 is a schematic diagram of an image of the same electronic component as in FIG. 5 captured by a conventionally known appearance inspection device. [Figure 9] FIG. 9 is a partially enlarged view of FIG. [Figure 10] FIG. 10 is an example of a binarized image obtained by binarizing the image shown in FIG. [Figure 11] FIG. 11 is a schematic diagram showing still another example of the appearance inspection apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The visual inspection device of the present invention will be described below. However, the present invention is not limited to the following configuration, and can be modified as appropriate within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual desirable configurations of the present invention described below.

[0012] In this specification, terms indicating the relationship between elements (e.g., "opposite," "orthogonal," etc.) and terms indicating the shape of an element (e.g., "rectangular prism") are not intended to be used in a strict sense, but are intended to include a substantially equal range, for example, a difference of a few percent.

[0013] The drawings shown below are schematic diagrams, and the dimensions, aspect ratios, and other scales may differ from those of the actual products.

[0014] The appearance inspection device of the present invention is characterized in that it comprises a stage on which an object to be imaged is placed, an illumination that irradiates illumination light onto the object to be imaged on the stage, an imaging unit that receives reflected light irradiated from the illumination and reflected by the object to be imaged on the stage to image the object to be imaged, a second polarizing filter that is arranged between the object to be imaged on the stage and the illumination and transmits illumination light that vibrates in a fixed direction, a first polarizing filter that is arranged between the object to be imaged on the stage and the imaging unit and transmits reflected light that vibrates in a direction different from the illumination light that has passed through the second polarizing filter, and a light shield that is arranged between the object to be imaged on the stage and the illumination and blocks illumination light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage.

[0015] FIG. 1 is a schematic diagram showing an example of a visual inspection apparatus of the present invention. The visual inspection apparatus 1 includes a stage 10 , an illumination device 20 , an imaging unit 30 , a first polarizing filter 40 , a second polarizing filter 50 , and a light blocking member 60 .

[0016] An object to be imaged 100 is placed on the stage 10 . Object 100 to be imaged has a substantially rectangular parallelepiped shape, and has ridges that are boundaries between two adjacent faces, and corners that are boundaries between three adjacent faces.

[0017] The illumination 20 irradiates the object to be imaged 100 on the stage 10 with illumination light. Illumination light emitted from the illumination 20 to the object 100 is reflected by the object 100 . The light reflected by the object to be imaged 100 is imaged by the imaging section 30. That is, the imaging section 30 images the object to be imaged 100 by receiving the light irradiated from the illumination 20 and reflected by the object to be imaged 100 on the stage 10.

[0018] Illumination light emitted from the illumination 20 passes through the second polarizing filter 50 , is reflected by the surface of the object to be imaged 100 on the stage 10 , passes through the first polarizing filter 40 , and is received by the imaging section 30 .

[0019] A light shield 60 is disposed between the object to be imaged 100 on the stage 10 and the illumination 20. Therefore, the light shield 60 can block the illumination light that does not pass through the second polarizing filter 50 from reaching the object to be imaged 100 on the stage 10.

[0020] The illumination light emitted from the illumination device 20 is received by the imaging unit 30 via the following path. First, the illumination light 20 a emitted from the illumination 20 is irradiated onto the second polarizing filter 50 and the light blocking object 60 . Of the illumination light 20a irradiated to the second polarizing filter 50, light in a vibration direction that can pass through the second polarizing filter 50 is irradiated onto the surface of the object to be imaged 100 on the stage 10 as transmitted light 20b that has passed through the second polarizing filter 50. Of the illumination light 20a irradiated to the second polarizing filter 50, light in a vibration direction that cannot pass through the second polarizing filter 50 is blocked by the second polarizing filter 50. Furthermore, the light irradiated to the light shielding object 60 is either blocked by the light shielding object 60 or reflected as reflected light 20c. The transmitted light 20b transmitted through the second polarizing filter 50 is irradiated onto the object to be imaged 100. The transmitted light 20b irradiated onto the object to be imaged 100 is reflected by the surface of the object to be imaged 100, and becomes reflected light 20d. A part of the reflected light 20d travels toward the first polarizing filter 40. Of the reflected light 20d that reaches the first polarizing filter 40, only light in a vibration direction that can pass through the first polarizing filter 40 is received by the imaging unit 30 as transmitted light 20e that has passed through the first polarizing filter 40.

[0021] Due to the presence of the light shield 60, all of the illumination light emitted from the light source 20 toward the object to be imaged 100 on the stage 10 becomes transmitted light (linearly polarized) 20b with a uniform vibration direction (polarization axis) after passing through the second polarizing filter 50. Therefore, the object 100 to be imaged is substantially illuminated with only the transmitted light (linearly polarized light) 20b that has passed through the second polarizing filter 50.

[0022] When the transmitted light (linearly polarized light) 20b transmitted through the second polarizing filter 50 is reflected by the object to be imaged 100, the manner in which the light is reflected varies depending on the condition of the surface of the object to be imaged 100. Specifically, on the surface of the object to be imaged 100, a smooth portion is likely to cause specular reflection, in which the polarization state does not change, while a rough portion is likely to cause diffuse reflection, in which the polarization state changes.

[0023] When the transmitted light (linearly polarized light) 20b that has passed through the second polarizing filter 50 is irradiated onto the ridges or corners of the object to be imaged 100, regular reflection without changing the polarization state is likely to occur because these surfaces are smooth. Therefore, the vibration direction (polarization axis) of the reflected light 20d that has reflected off the ridges or corners is the same as that of the transmitted light 20b that has passed through the second polarizing filter 50, and it is difficult for it to pass through the first polarizing filter 40. Therefore, in the image captured by the imaging unit 30, the ridges and corners are displayed as "dark areas", making it possible to suppress light reflection on the ridges and dark areas.

[0024] On the other hand, when the transmitted light (linearly polarized light) 20b that has passed through the second polarizing filter 50 is irradiated onto a crack or chip in the object to be imaged 100, these surfaces are uneven and not smooth, and thus diffuse reflection, which changes the polarization state, is likely to occur. Specifically, since the polarization state is not maintained between the incident light and the reflected light, the vibration direction (polarization axis) of the reflected light 20d reflected by the crack or chip in the object to be imaged 100 differs from the vibration direction (polarization axis) of the transmitted light 20b that has passed through the second polarizing filter 50, and the reflected light is likely to pass through the first polarizing filter 40. Therefore, in the image captured by the imaging unit 30, cracks and chips are displayed as "bright areas," and when a crack or chip exists on a ridge or corner where light reflection is suppressed, it becomes possible to identify the crack or chip.

[0025] For the reasons described above, by using the visual inspection device of the present invention, light reflection at ridges and corners can be suppressed, so that clear images can be obtained even if cracks, chips, etc. are formed on curved surfaces such as ridges and corners.

[0026] In addition, if illumination light 20a that has not passed through the second polarizing filter 50 is irradiated from the illumination 20 toward the object to be imaged 100 on the stage 10, the light irradiated to the object to be imaged 100 will include illumination light that has not passed through the second polarizing filter 50 (light that is not linearly polarized). Such non-linearly polarized light passes through the first polarizing filter 40 regardless of which surface of the object to be imaged 100 it is reflected from, so the light reflected from the ridges and corners passes through the first polarizing filter 40 and is imaged as a "bright area" by the imaging section 30. As a result, it is not possible to suppress the reflection of light from the ridges and corners, and it is not possible to obtain a clear image in which cracks or chips can be identified.

[0027] (stage) An object to be imaged is placed on the stage. The material that constitutes the stage is not particularly limited. The stage is preferably made of a material that absorbs or transmits light.

[0028] (illumination) The illumination irradiates an object to be imaged on the stage with illumination light.

[0029] The wavelength of the irradiated light preferably includes at least a part of the wavelength range of, for example, 400 nm to 1200 nm.

[0030] The light source of the illumination may be any light source that includes at least some of the above-mentioned wavelengths, and examples thereof include light-emitting diodes, halogen lamps, HID lamps, low-pressure discharge lamps, and xenon lamps.

[0031] A plurality of light sources may be arranged within the lighting device.

[0032] (Second polarizing filter) The second polarizing filter is disposed between the object to be imaged on the stage and the illumination. The second polarizing filter transmits illumination light that vibrates in a certain direction.

[0033] (Shading) The light blocking object is disposed between the object to be imaged on the stage and the illumination.

[0034] The light blocking object blocks the illumination light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage.

[0035] The shape of the light blocking object may be any shape that can block light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage, and examples of such shapes include a cylinder, a box, and a wall.

[0036] For example, by placing a light source inside a box-shaped light shielding object having an opening, covering the opening with a second polarizing filter, and positioning the second polarizing filter facing the object to be imaged, the light shielding object can block the illumination light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage.

[0037] (Imaging unit) The imaging section receives light that is irradiated from an illumination source and reflected off an object to be imaged on the stage, and captures an image of the object to be imaged.

[0038] The imaging section is preferably disposed so as to face an object to be imaged on the stage.

[0039] The imaging unit may be, for example, a camera equipped with a CCD image sensor or a CMOS image sensor.

[0040] The resolution of the image obtained by the imaging unit is not particularly limited, but is preferably 400,000 pixels or more and 2 million pixels or less. If the resolution of the image obtained by the imaging unit is less than 400,000 pixels, the resolution is low and it may not be possible to detect minute cracks or chips. Furthermore, if the resolution of the image obtained by the imaging unit exceeds 2 million pixels, the amount of data per image becomes too large, which may result in a long time being required for binarization processing and for determining whether there are cracks or chips.

[0041] (First polarizing filter) The first polarizing filter is disposed between the image capturing unit and the object to be imaged on the stage.

[0042] The first polarizing filter transmits illumination light that vibrates in a certain direction. The direction in which the light transmitted through the first polarizing filter vibrates (polarization axis) is different from the direction in which the light transmitted through the second polarizing filter vibrates (polarization axis). Therefore, the light that has passed through the second polarizing filter cannot pass through the first polarizing filter.

[0043] It is preferable that the polarization axis of the first polarizing filter and the polarization axis of the second polarizing filter are offset by 87° or more and 93° or less, more preferably 88° or more and 92° or less, even more preferably 89° or more and 91° or less, and most preferably 90°.

[0044] The first polarizing filter and the second polarizing filter may be the same type of polarizing filters, but may be arranged such that their polarization axes are not aligned, for example, by 90°.

[0045] (Ring Light) The illumination is preferably a hollow-core ring illumination. An air-core ring light is a ring-shaped (annular) light that has an air-core (or simply a core) that serves as a hollow portion in the center.

[0046] When the illumination is a ring illumination, the second polarizing filter is preferably arranged in a circular shape on the ring illumination.

[0047] When the illumination is a ring illumination, it is preferable that the light blocking object is cylindrical and covers the periphery of the core of the ring illumination.

[0048] When the illumination is a ring illumination, it is preferable that the outer tube and the top surface of the ring illumination are also made of a light-shielding material.

[0049] An example of a ring illumination will be described with reference to FIGS.

[0050] FIG. 2 is a perspective view illustrating a schematic example of a ring illumination. FIG. 3 is a cross-sectional view taken along line AA in FIG.

[0051] The ring light 21 shown in FIG. 2 is a ring-shaped light having an air core 22 in the center. As shown in FIG. 3, a plurality of LEDs 23 serving as light sources are arranged inside the ring illumination 21 facing upward. A cylindrical light shield 61 is disposed in hollow core 22 of ring illumination 21 so as to cover the core. Furthermore, a second polarizing filter 51 is provided above the ring illumination 21. The second polarizing filter 51 has an annular shape, similar to the ring illumination. A tip 61a of the cylindrical light shield 61 protrudes further toward the stage 10 side (upper side of the paper surface) than the second polarizing filter 51.

[0052] The above-mentioned ring illumination can also be used as illumination for the appearance inspection device shown in FIG. Furthermore, when a ring illumination is used as the illumination, the ring illumination and the imaging unit can be arranged on the same axis, unlike the appearance inspection device shown in Figure 1. This configuration contributes to the miniaturization of the appearance inspection device.

[0053] An example of an appearance inspection device in which a ring illumination and an imaging unit are arranged on the same axis will be described with reference to FIG.

[0054] FIG. 4 is a schematic diagram showing an example of an appearance inspection apparatus in which the ring illumination shown in FIGS. 2 and 3 is arranged coaxially with an imaging section. The appearance inspection apparatus 2 shown in FIG. 4 includes a stage 10, a ring illumination 21, an imaging section 30, a first polarizing filter 40, a second polarizing filter 51, and a light blocking member 61. The ring illumination 21 is the ring illumination shown in FIGS. However, the ring illumination 21 shown in FIG. 4 is obtained by inverting the ring illumination 21 shown in FIG.

[0055] 4, the central axis (not shown) of the air core 22 of the ring illumination 21 and the central axis (not shown) of the imaging unit 30 are arranged to overlap with each other. Therefore, in the visual inspection device 2, it can be said that the ring illumination 21 and the imaging unit 30 are arranged on the same axis.

[0056] A cylindrical light shield 61 is provided to cover the hollow core 22 of the ring illumination 21 , so that the illumination light 21 a emitted from the LED 23 of the ring illumination 21 does not reach the object 100 to be imaged on the stage 10 .

[0057] The illumination light emitted from the ring illumination 21 is received by the imaging section 30 via the following path. First, the illumination light 21 a emitted from the LED 23 of the ring illumination 21 is irradiated onto the second polarizing filter 51 or the light blocking member 61 . Of the illumination light 21a irradiated to the second polarizing filter 51, light in a vibration direction that can pass through the second polarizing filter 51 is irradiated onto the surface of the object to be imaged 100 on the stage 10 as transmitted light 21b that has passed through the second polarizing filter 51. Of the illumination light 21a irradiated to the second polarizing filter 51, light in a vibration direction that cannot pass through the second polarizing filter 51 is absorbed or reflected by the second polarizing filter 51. Furthermore, the illumination light 21 a irradiated onto the light blocking material 61 is reflected or absorbed by the light blocking material 61 . Therefore, all of the illumination light 21a emitted from the ring illumination 21 toward the object to be imaged 100 on the stage 10 passes through the second polarizing filter 51 and becomes transmitted light (linearly polarized light) 21b with a uniform vibration direction (polarization axis).

[0058] The transmitted light 21b transmitted through the second polarizing filter 51 is irradiated onto the object 100 to be imaged. The transmitted light 21b irradiated onto the object 100 is reflected by the surface of the object 100 and becomes reflected light 21d. Since the air core 22 of the ring illumination 21 and the imaging unit 30 are arranged on the same axis, a portion of the reflected light 21d passes through the air core 22 of the ring illumination 21 and travels toward the first polarizing filter 40. Of the reflected light 21d that reaches the first polarizing filter 40, only light in a vibration direction that can pass through the first polarizing filter 40 is received by the imaging unit 30 as transmitted light 21e that has passed through the first polarizing filter 40.

[0059] In the visual inspection device of the present invention, the illumination is an air-core ring illumination and is arranged so that light reflected by the object to be imaged passes through the core and is received by the imaging unit, the second polarizing filter is arranged in a circular ring shape on the ring illumination, and the light shield is preferably cylindrical and covers the periphery of the core of the ring illumination.

[0060] In the appearance inspection device 2 shown in Figure 4, the illumination is an air-core ring illumination 21, which is arranged so that reflected light 21d reflected by the object to be imaged 100 passes through the core (air-core 22) and is received by the imaging section 30, a second polarizing filter 51 is arranged in a circular ring shape on the ring illumination 21, and a light shielding member 61 is cylindrical and covers the periphery of the core of the ring illumination 21.

[0061] It is preferable that the cylindrical light blocking object protrudes toward the stage side beyond the second polarizing filter. If the cylindrical light-shielding object protrudes toward the stage side beyond the second polarizing filter, light reflected from an object other than the object to be imaged can be prevented from entering the hollow core of the ring light, thereby suppressing the intrusion of unnecessary light into the imaging section.

[0062] In the appearance inspection apparatus 2 shown in FIG. 4, a cylindrical light shield 61 provided to cover the core of the ring illumination 21 has a tip 61a that protrudes further toward the stage 10 than the second polarizing filter 51.

[0063] In the appearance inspection device 2 shown in Figure 4, the first polarizing filter 40 and the imaging unit 30 are arranged on the same axis as the air core of the ring illumination 21, and farther away from the stage 10 than the ring illumination 21 (on the opposite side from the stage 10); however, the first polarizing filter 40 and the imaging unit 30 may also be arranged within the air core 22 of the ring illumination 21.

[0064] Next, an example of a method for inspecting the appearance of an electronic component using the appearance inspection apparatus of the present invention will be described. An image of an object captured using the visual inspection device of the present invention suppresses light reflection at ridges and corners, and cracks, chips, etc. are clearly visible. Then, by subjecting the image captured by the imaging unit to image processing, it may be possible to more easily determine whether there are any cracks or chips. This will be explained with reference to FIGS. 5 to 7 and 8 to 10.

[0065] Fig. 5 is a schematic diagram of an image of an electronic component having a crack or chip on a ridge line, captured by the visual inspection device of the present invention. Fig. 6 is a partial enlarged view of Fig. 5. Fig. 7 is an example of a binarized image obtained by binarizing the image shown in Fig. 6. Fig. 8 is a schematic diagram of an image of the same electronic component as Fig. 5, captured by a conventionally known visual inspection device. Fig. 9 is a partial enlarged view of Fig. 8. Fig. 10 is an example of a binarized image obtained by binarizing the image shown in Fig. 9.

[0066] 5 and 8 are examples of images of the same electronic component having external electrodes. It can be seen from both images of FIG. 5 and FIG. 8 that a crack / chip 100A exists at the ridge line. 6 and 9, it can be seen that in FIG. 6, the reflection of light at the ridgeline portion 100B is suppressed, but in FIG. 9, the reflection of light at the ridgeline portion 100B cannot be suppressed. Furthermore, comparing Figures 7 and 10, it can be seen that in Figure 7, only the areas in the binarized image where cracks or chips 100A occur are judged to be "bright areas," whereas in Figure 10, both the cracks or chips 100A and the ridge lines 100B are judged to be "bright areas" in the binarized image. In other words, in an image captured using the visual inspection device of the present invention shown in Figure 7, it is possible to distinguish between reflections due to cracks or chips present on the ridge line and reflections from the ridge line itself, and to recognize only the reflected light due to the cracks or chips.

[0067] (Object to be imaged) The object to be imaged by the visual inspection apparatus of the present invention is, for example, an electronic component equipped with external electrodes. That is, the visual inspection apparatus of the present invention can be suitably used for visual inspection of electronic components equipped with external electrodes.

[0068] Examples of electronic components having external electrodes include multilayer ceramic capacitors, inductors, thermistors, and resistors.

[0069] The shape of the object to be imaged is not particularly limited, but may be, for example, a substantially rectangular parallelepiped shape with a length of 0.1 to 3.2 mm, and a thickness and width of 0.05 to 1.6 mm.

[0070] The object to be imaged may be illuminated with natural light. Natural light has a lower intensity than the light irradiated from the lighting through the second polarizing filter, so it has almost no effect on the appearance inspection results of the object to be imaged.

[0071] FIG. 11 is a schematic diagram showing still another example of the appearance inspection apparatus of the present invention.

[0072] The appearance inspection device 3 includes a feeder 110 that supplies electronic components as objects to be imaged, and a stage 10 on which the objects to be imaged are placed and rotated. The stage 10 has inspection areas 131, 132, 133, 134, 135, and 136 for inspecting the appearance of the objects to be imaged, and a classification area 140 for classifying the objects to be imaged based on the inspection results in the inspection areas.

[0073] An object to be imaged is supplied onto the stage 10 from a feeder 110 at regular intervals.

[0074] The stage 10 is disk-shaped, and an object to be imaged is placed near the edge thereof. As the stage 10 rotates, the object to be imaged that is placed near the edge is transported to the inspection areas 131, 132, 133, 134, 135, and 136 in order.

[0075] The appearance of the object to be imaged is inspected in the inspection areas 131 to 136. The method of the appearance inspection is as described above.

[0076] When the object to be imaged has a hexahedral shape, for example, each of the inspection areas 131, 132, 133, 134, 135, and 136 may inspect one surface of the object to be imaged.

[0077] There may be a plurality of inspection areas as shown in FIG. 11, but there may also be only one.

[0078] The objects to be imaged may be classified in the classification area 140 according to the results of the appearance inspection in the inspection area.

[0079] One method for sorting them is, for example, pushing them out of the stage (blowing them off) with compressed air. The object to be imaged may be moved using a robot arm.

[0080] Also, instead of the sorting area 140, a first discharge area for discharging defective products and a second discharge area for discharging non-defective products may be provided depending on the inspection results in the inspection areas 131 to 136, and the objects to be imaged may be sorted depending on the judgment results.

[0081] Although not shown in FIG. 11, a control unit may be provided to control the rotation speed of the stage, to binarize the image captured by the imaging unit, and to determine whether the captured object has any cracks or chips based on the binarized image.

[0082] This specification describes the following:

[0083] The present disclosure (1) relates to a stage on which an object to be imaged is placed; an illumination device that irradiates the object to be imaged on the stage with illumination light; an imaging unit that receives light that is irradiated from the illumination and reflected by the object to be imaged on the stage, and images the object to be imaged; a second polarizing filter disposed between the object to be imaged on the stage and the illumination, the second polarizing filter transmitting illumination light oscillating in a fixed direction; a first polarizing filter that is disposed between the object to be imaged on the stage and the imaging unit and transmits reflected light that vibrates in a direction different from that of the illumination light that has been transmitted through the second polarizing filter; This is an appearance inspection device characterized by comprising a light shield that is placed between the object to be imaged on the stage and the lighting, and that blocks illumination light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage.

[0084] The present disclosure (2) relates to a ring light having an air-core, and is arranged so that light reflected by the object to be imaged passes through the core and is received by the imaging unit; the second polarizing filter is disposed in a circular shape on the ring illumination; The visual inspection device according to the present disclosure (1) is characterized in that the light-shielding object is cylindrical and covers the periphery of the core of the ring illumination.

[0085] The present disclosure (3) is the appearance inspection device according to the present disclosure (2), wherein the cylindrical light blocking object protrudes toward the stage side beyond the second polarizing filter.

[0086] The present disclosure (4) is a visual inspection device used for visual inspection of electronic components equipped with external electrodes, which is arbitrarily combined with any of the present disclosures (1) to (3). [Explanation of symbols]

[0087] 1, 2, 3 Visual inspection equipment 10 Stages 20. Lighting 20a Illumination light 20b Light transmitted through the second polarizing filter 20c Reflected light reflected by a shaded object 20d Light reflected from the object being imaged 20e Light transmitted through the first polarizing filter 21 Ring Light 21a illumination light 21b Light transmitted through the second polarizing filter 21d Light reflected by the object being imaged 21e Light transmitted through the first polarizing filter 22 Ring Lighting Hollow Core 30 Imaging unit 40 First polarizing filter 50, 51 Second polarizing filter 60 Shading 61 Cylindrical light shield 61a Tip of cylindrical light shield 100 Imaged object 100A Cracks / chips 100B Ridge 110 Feeder 131, 132, 133, 134, 135, 136 Inspection Area 140 Classification Area

Claims

1. a stage on which an object to be imaged is placed; an illumination device that irradiates the object to be imaged on the stage with illumination light; an imaging unit that receives light that is irradiated from the illumination and reflected by the object to be imaged on the stage, and images the object to be imaged; a second polarizing filter disposed between the object to be imaged on the stage and the illumination, the second polarizing filter transmitting illumination light oscillating in a fixed direction; a first polarizing filter that is disposed between the object to be imaged on the stage and the imaging unit and transmits reflected light that vibrates in a direction different from that of the illumination light that has been transmitted through the second polarizing filter; and a light shield disposed between the object to be imaged on the stage and the lighting, which blocks illumination light that does not pass through the second polarizing filter from reaching the object to be imaged on the stage.

2. the illumination is an air-core ring illumination, and is disposed so that light reflected by the object to be imaged passes through an interior of the core and is received by the imaging unit; the second polarizing filter is disposed in a circular shape on the ring illumination; 2. The visual inspection apparatus according to claim 1, wherein the light blocking member is cylindrical and covers a periphery of the core of the ring illumination.

3. 3. The visual inspection apparatus according to claim 2, wherein the cylindrical light blocking member protrudes toward the stage side beyond the second polarizing filter.

4. 4. The visual inspection apparatus according to claim 1, which is used for visual inspection of an electronic component having external electrodes.

Images