Inspection equipment

Abstract

To provide an inspection device for inspecting presence / absence of defects on a surface of an inspected object having translucency.SOLUTION: An inspection device 1 includes: an illumination unit 21 that includes one surface 60S1 curved in a convex shape and the other surface 60S2 that opposes the one surface 60S1 and is curved in a recessed shape, is disposed in a side of the other surface 60S2 on the basis of an inspected object 60 that has translucency and is used for a lighting fixture, and applies light to the other surface 60S2; an imaging unit 30 that is disposed in the side of one surface 60S1 on the basis of the inspected object 60 and images light from the illumination unit 21 that is transmitted through the inspected object 60; an inspection section 40 for determining presence / absence of defects on one surface 60S1 and the other surface 60S2 of the inspected object 60 on the basis of the image captured by the imaging unit 30; and a transparent support film 13 that crosses between the illumination unit 21 and the imaging unit 31 and conveys the inspected object 60.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inspection apparatus for inspecting the presence or absence of defects on the surface of a translucent inspection object.

Background Art

[0002] In an inspection apparatus for inspecting the presence or absence of defects on the surface of a translucent inspection object, various configurations have been studied to improve the detection accuracy of defects. For example, Patent Document 1 below discloses an inspection apparatus including an illumination unit that irradiates light on a translucent inspection object, and an imaging unit that faces the illumination unit with the inspection object interposed therebetween and images light from the illumination unit that passes through the inspection object. In this inspection apparatus, the presence or absence of defects on the surface of the inspection object is determined based on an image captured by the imaging unit.

[0003]

Patent Document 1

Summary of the Invention

[0004] For example, in order to inspect defects such as foreign matter adhering to the surface of an outer cover that transmits light in a lamp, it is conceivable to use the inspection apparatus described in Patent Document 1 above. Generally, an outer cover includes a front surface that curves convexly and a rear surface that curves concavely and faces the front surface. In addition, ribs protruding from the rear surface may be provided on the outer peripheral edge of the outer cover, and for example, these ribs are attached to other members of the lamp.

[0005] An inspection apparatus according to a first aspect of the present invention is characterized by comprising: an illumination unit positioned on the other surface side of an object to be inspected, with respect to the object to be inspected which is translucent and includes one surface that is curved in a convex shape and the other surface that is curved in a concave shape opposite to the one surface, and irradiating the other surface with light; an imaging unit positioned on the one surface side of the object to be inspected with respect to the object to be inspected, and imaging the light from the illumination unit that passes through the object to be inspected; and an inspection unit that determines whether or not there are defects on the one surface and the other surface of the object to be inspected based on the image captured by the imaging unit.

[0006] In the inspection apparatus of the first embodiment, the illumination unit irradiates light onto the other surface which is curved in a concave shape. For example, if a rib is provided on the outer edge of the object to be inspected that protrudes from the other surface, the light from the illumination unit may be reflected by the boundary between the rib and the other surface, or by the rib, etc., and directed toward the other surface. In this way, a portion of the light directed toward the other surface is reflected by that other surface. In the inspection apparatus of the first embodiment, as described above, the imaging unit is positioned on one side relative to the object to be inspected, so that the light reflected from the other surface in this way does not enter the imaging unit. In addition, another portion of the light directed toward the other surface enters the object to be inspected from the other surface and exits from the one surface. In the inspection apparatus of the first embodiment, as described above, one surface is curved in a convex shape, so that the light that enters the object to be inspected from the other surface in this way can be diffused and exited from the one surface, and the entry of this light into the imaging unit is suppressed. Therefore, light from the lighting unit is less likely to be reflected by the boundary between the rib and the other surface, or by the rib itself, and this reflected light is less likely to be captured in the image taken by the imaging unit. Accordingly, this inspection apparatus in the first embodiment can suppress a decrease in the accuracy of detecting surface defects of the object to be inspected, even when ribs protruding from the other surface are provided on the outer edge of the object to be inspected.

[0007] Furthermore, in the inspection apparatus of the first embodiment, the illumination unit may have a first illumination unit that irradiates light onto the other surface of the object to be inspected from a first direction, and a second illumination unit that irradiates light onto the other surface of the object to be inspected from a second direction different from the first direction, and the imaging unit may separately image the light from the first illumination unit and the light from the second illumination unit that passes through the object to be inspected.

[0008] In the inspection apparatus of the first embodiment, the inspection unit determines the presence or absence of defects based on an image captured by light from a first illumination unit that is irradiated from a first direction onto the other surface of the object under inspection and passes through the object under inspection. Furthermore, the inspection unit determines the presence or absence of defects based on an image captured by light from a second illumination unit that is irradiated from a second direction different from the first direction onto the other surface of the object under inspection and passes through the object under inspection. In other words, the inspection unit determines the presence or absence of defects in both cases: when light is irradiated from the first direction onto the other surface of the object under inspection by the first illumination unit, and when light is irradiated from the second direction different from the first direction onto the other surface of the object under inspection by the second illumination unit. Since the first and second directions are different from each other, the absorption, reflection, refraction, etc. of light caused by defects in the object under inspection when light is irradiated from the first direction will be different from when light is irradiated from the second direction. Therefore, defects that were difficult to detect in the image when light is irradiated from the first direction may become easier to detect in the image when light is irradiated from the second direction, and defects that were difficult to detect in the image when light is irradiated from the second direction may become easier to detect in the image when light is irradiated from the second direction. For this reason, the inspection apparatus of the first embodiment can suppress a decrease in the accuracy of detecting defects in the object under inspection compared to the case in which the illumination unit does not have a second illumination section.

[0009] Furthermore, in the inspection apparatus of the first embodiment, if the lighting unit has a first lighting section and a second lighting section, the timing at which the first lighting section irradiates the other surface of the object to be inspected and the timing at which the second lighting section irradiates the other surface of the object to be inspected may be different from each other.

[0010] With this configuration, the light from the second illumination unit does not appear in the image captured by the light from the first illumination unit. Similarly, the light from the first illumination unit does not appear in the image captured by the light from the second illumination unit. Therefore, the imaging unit does not need to have, for example, a first imaging unit for imaging the light from the first illumination unit and a second imaging unit for imaging the light from the second illumination unit; instead, it can capture the light from the first illumination unit and the light from the second illumination unit separately.

[0011] Furthermore, in the inspection apparatus of the first embodiment, if the illumination unit has a first illumination section and a second illumination section, the imaging unit may intersect a first straight line parallel to the optical axis of the first illumination section and passing through the light emission surface of the first illumination section, and not intersect a second straight line parallel to the optical axis of the second illumination section and passing through the light emission surface of the second illumination section, and the inspection section may determine the absence of defects from the dark areas in the image captured by the light from the first illumination section, and determine the presence or absence of defects from the bright areas in the image captured by the light from the second illumination section.

[0012] When an object under inspection has a defect, much of the light that enters the defect is absorbed or reflected by the defect. On the other hand, much of the light that does not enter the defect passes through the object under inspection. In the inspection apparatus of the first embodiment, as described above, the imaging unit is parallel to the optical axis of the first illumination unit and intersects with a first straight line passing through the light emission surface of the first illumination unit. Therefore, the imaging unit can image the light from the first illumination unit that does not enter the defect and passes through the object under inspection. As a result, defects can be displayed as dark areas in the image captured by the light from the first illumination unit. Furthermore, in the inspection apparatus of the first embodiment, as described above, the imaging unit is parallel to the optical axis of the second illumination unit and does not intersect with a second straight line passing through the light emission surface of the second illumination unit. Therefore, the imaging unit can image the light from the second illumination unit that enters the defect and is reflected by the defect, while not image the light that does not enter the defect and passes through the object under inspection. As a result, defects can be displayed as bright areas in the image captured by the light from the second illumination unit. Incidentally, because light propagates while diffusing, if the defect is thin and fibrous, such as a strand of hair or thread, such a defect tends not to appear as a dark area in the image captured by the light from the first illumination unit. However, in the inspection apparatus of the first embodiment, such defects can be made to appear as bright areas in the image captured by the light from the second illumination unit. Therefore, the inspection apparatus of the first embodiment can detect even thin defects such as fibrous foreign objects.

[0013] Alternatively, if the illumination unit has a first illumination unit and a second illumination unit, the imaging unit may have a first imaging unit that images the light from the first illumination unit that passes through the object to be inspected, and a second imaging unit that images the light from the second illumination unit that passes through the object to be inspected, wherein the first imaging unit intersects with a first straight line parallel to the optical axis of the first illumination unit and passing through the light emission surface of the first illumination unit, and the second imaging unit does not intersect with a second straight line parallel to the optical axis of the second illumination unit and passing through the light emission surface of the second illumination unit, and the inspection unit may determine the presence or absence of the defect from the dark areas in the image captured by the first imaging unit and from the bright areas in the image captured by the second imaging unit.

[0014] In the inspection apparatus of the first embodiment, as described above, the first imaging unit intersects with a first straight line that is parallel to the optical axis of the first illumination unit and passes through the light emission surface of the first illumination unit. Therefore, as described above, defects can be displayed as dark areas in the image captured by the first imaging unit using light from the first illumination unit. Also, as described above, the second imaging unit does not intersect with a second straight line that is parallel to the optical axis of the second illumination unit and passes through the light emission surface of the second illumination unit. Therefore, as described above, defects can be displayed as bright areas in the image captured by the second imaging unit using light from the second illumination unit. Consequently, even with an inspection apparatus of this configuration, it is possible to detect fine defects such as fibrous foreign matter.

[0015] Furthermore, in the inspection apparatus of the first embodiment, when the imaging unit intersects with the first straight line but not with the second straight line, and when the imaging unit has a first imaging unit and a second imaging unit, the light from the second illumination unit may be collimated light or light focused on the other surface of the object under inspection.

[0016] By adopting this configuration, the brightness of the bright areas when defects are displayed as bright areas can be increased compared to when the light from the second illumination unit is diffused light, thereby increasing the detection accuracy of thin defects such as fibrous foreign matter.

[0017] Furthermore, in the inspection apparatus of the first embodiment, the imaging unit has a first imaging unit that images light from the illumination unit that is parallel to the optical axis of the illumination unit, intersects with a straight line passing through the light emission surface of the illumination unit, and transmits light through the object to be inspected, and a second imaging unit that images light from the illumination unit that does not intersect with the straight line and transmits light through the object to be inspected, and the inspection unit may determine the presence or absence of the defect from the dark areas in the image captured by the first imaging unit and from the bright areas in the image captured by the second imaging unit.

[0018] In the inspection apparatus of the first embodiment, as described above, the first imaging unit is parallel to the optical axis of the illumination unit and intersects with a straight line passing through the light emission surface of the illumination unit. Therefore, as described above, defects can be displayed as dark areas in the image captured by the first imaging unit of light from the illumination unit. Also, as described above, the second imaging unit is parallel to the optical axis of the illumination unit and does not intersect with a straight line passing through the light emission surface of the illumination unit. Therefore, as described above, defects can be displayed as bright areas in the image captured by the second imaging unit of light from the illumination unit. Consequently, even with an inspection apparatus of this configuration, it is possible to detect fine defects such as fibrous foreign matter.

[0019] A second aspect of the present invention provides an inspection apparatus comprising: an illumination unit positioned on the side of one surface of an object to be inspected, with respect to the object having a translucent surface including one surface that curves convexly and the other surface that curves concavely opposite to the one surface, and irradiating the one surface with light; an imaging unit positioned on the side of the other surface of the object to be inspected, with respect to the object to be inspected, and imaging the light from the illumination unit that passes through the object to be inspected; and an inspection unit that determines whether or not there are defects on the one surface and the other surface of the object to be inspected based on the image captured by the imaging unit.

[0020] For example, if a rib is provided on the outer edge of the object under inspection, protruding from the other surface, light transmitted through the rib or reflected by the rib may appear in the image captured by the imaging unit. When such a rib is provided, and the illumination unit is positioned on the other side of the object under inspection, and the imaging unit is positioned on the one side of the object under inspection, the light from the illumination unit that travels from the rib to the imaging unit tends to travel via the other or one surface near the rib to the imaging unit. In this case, much of the light traveling from the rib to the imaging unit tends to overlap with the light that travels to the imaging unit via the other or one surface near the rib without passing through the rib, and thus enters the imaging unit. In other words, in the image captured by the imaging unit, the light from the rib tends to overlap with the other or one surface near the rib. Therefore, the light traveling from the rib to the imaging unit tends to make it difficult to properly detect defects on the other or one surface near the rib. On the other hand, in the inspection apparatus according to the second embodiment, as described above, the illumination unit is positioned on one side of the object under inspection with respect to the object under inspection, and the imaging unit is positioned on the other side of the object under inspection with respect to the object under inspection. Therefore, when ribs protruding from the other side are provided on the outer edge of the object under inspection as described above, some of the light from the illumination unit that enters the object under inspection from one side, and some of the light that enters the object under inspection from one side and exits from the other side of the object under inspection, may enter the ribs or be reflected by the ribs and head towards the imaging unit. Even if light heads towards the imaging unit from the ribs in this way, it is easy for this light to head towards the imaging unit without passing through the other side or the one side in the vicinity of the ribs. Therefore, compared to the case where the illumination unit is positioned on the other side of the object under inspection and the imaging unit is positioned on one side of the object under inspection, even if light is directed from the rib towards the imaging unit, this light is less likely to overlap with light directed towards the imaging unit via the other or one side near the rib without passing through the rib, thereby suppressing the inability to properly detect defects on the other or one side near the rib.Therefore, the inspection apparatus according to the second embodiment can suppress the narrowing of the inspection range for surface defects of the object to be inspected, even if ribs are provided on the outer edge of the object to be inspected that protrude from the other surface and light is directed from the ribs towards the imaging unit.

[0021] Furthermore, in the inspection apparatus of the second embodiment, the illumination unit may have a first illumination unit that irradiates light onto one surface of the object to be inspected from a first direction, and a second illumination unit that irradiates light onto the one surface of the object to be inspected from a second direction different from the first direction, and the imaging unit may separately image the light from the first illumination unit and the light from the second illumination unit that passes through the object to be inspected.

[0022] In the inspection apparatus according to the second embodiment, the inspection unit determines the presence or absence of defects based on an image captured by light from a first illumination unit that is irradiated onto one surface of the object under inspection from a first direction and passes through the object under inspection. Furthermore, the inspection unit determines the presence or absence of defects based on an image captured by light from a second illumination unit that is irradiated onto one surface of the object under inspection from a second direction different from the first direction and passes through the object under inspection. In other words, the inspection unit determines the presence or absence of defects in both cases: when light is irradiated onto one surface of the object under inspection from a first direction by the first illumination unit, and when light is irradiated onto one surface of the object under inspection from a second direction different from the first direction by the second illumination unit. Since the first and second directions are different from each other, the absorption, reflection, refraction, etc. of light caused by defects in the object under inspection when light is irradiated from the first direction will be different from when light is irradiated from the second direction. Therefore, defects that were difficult to detect in the image when light is irradiated from the first direction may become easier to detect in the image when light is irradiated from the second direction, and defects that were difficult to detect in the image when light is irradiated from the second direction may become easier to detect in the image when light is irradiated from the second direction. For this reason, the inspection apparatus according to the second embodiment can suppress a decrease in the accuracy of detecting defects in the inspected object compared to the case in which the illumination unit does not have a second illumination section.

[0023] Furthermore, in the inspection apparatus of the second embodiment, if the lighting unit has a first lighting unit and a second lighting unit, the timing at which the first lighting unit irradiates light onto one surface of the object to be inspected and the timing at which the second lighting unit irradiates light onto the one surface of the object to be inspected may be different from each other.

[0024] With this configuration, the light from the second illumination unit does not appear in the image captured by the light from the first illumination unit. Similarly, the light from the first illumination unit does not appear in the image captured by the light from the second illumination unit. Therefore, the imaging unit does not need to have, for example, a first imaging unit for imaging the light from the first illumination unit and a second imaging unit for imaging the light from the second illumination unit; instead, it can capture the light from the first illumination unit and the light from the second illumination unit separately.

[0025] Furthermore, in the inspection apparatus of the second embodiment, if the illumination unit has a first illumination unit and a second illumination unit, the imaging unit may intersect a first straight line parallel to the optical axis of the first illumination unit and passing through the light emission surface of the first illumination unit, and not intersect a second straight line parallel to the optical axis of the second illumination unit and passing through the light emission surface of the second illumination unit, and the inspection unit may determine the absence of the defect from the dark areas in the image captured by the light from the first illumination unit, and determine the presence or absence of the defect from the bright areas in the image captured by the light from the second illumination unit.

[0026] When an object under inspection has a defect, much of the light that enters the defect is absorbed or reflected by the defect. On the other hand, much of the light that does not enter the defect passes through the object under inspection. In the inspection apparatus according to the second embodiment, as described above, the imaging unit is parallel to the optical axis of the first illumination unit and intersects with a first straight line passing through the light emission surface of the first illumination unit. Therefore, the imaging unit can image the light from the first illumination unit that does not enter the defect and passes through the object under inspection. As a result, defects can be displayed as dark areas in the image captured by the light from the first illumination unit. Furthermore, in the inspection apparatus according to the second embodiment, as described above, the imaging unit is parallel to the optical axis of the second illumination unit and does not intersect with a second straight line passing through the light emission surface of the second illumination unit. Therefore, the imaging unit can image the light from the second illumination unit that enters the defect and is reflected by the defect, while not image the light that does not enter the defect and passes through the object under inspection. As a result, defects can be displayed as bright areas in the image captured by the light from the second illumination unit. Incidentally, because light propagates while diffusing, if the defect is thin and fibrous, such as a strand of hair or thread, such a defect tends not to appear as a dark area in the image captured by the light from the first illumination unit. However, in the inspection device according to the second embodiment, such defects can be made to appear as bright areas in the image captured by the light from the second illumination unit. Therefore, this inspection device can detect defects even if they are thin, such as fibrous foreign objects.

[0027] Alternatively, if the illumination unit has a first illumination unit and a second illumination unit, the imaging unit may have a first imaging unit that images the light from the first illumination unit that passes through the object to be inspected, and a second imaging unit that images the light from the second illumination unit that passes through the object to be inspected, wherein the first imaging unit intersects with a first straight line parallel to the optical axis of the first illumination unit and passing through the light emission surface of the first illumination unit, and the second imaging unit does not intersect with a second straight line parallel to the optical axis of the second illumination unit and passing through the light emission surface of the second illumination unit, and the inspection unit may determine the presence or absence of the defect from the dark areas in the image captured by the first imaging unit and from the bright areas in the image captured by the second imaging unit.

[0028] In this inspection apparatus according to the second aspect, as described above, the first imaging unit intersects a first straight line that is parallel to the optical axis of the first illumination unit and passes through the light-emitting surface of the light of the first illumination unit. Therefore, as described above, in the image captured by the first imaging unit of the light from the first illumination unit, a defect can be displayed as a dark portion. Further, as described above, the second imaging unit does not intersect a second straight line that is parallel to the optical axis of the second illumination unit and passes through the light-emitting surface of the light of the second illumination unit. Therefore, as described above, in the image captured by the second imaging unit of the light from the second illumination unit, a defect can be displayed as a bright portion. Accordingly, even in an inspection apparatus having such a configuration, thin defects such as fibrous foreign matter can be detected.

[0029] Also, in the inspection apparatus of the second aspect, when the imaging unit intersects the first straight line and does not intersect the second straight line, and when the imaging unit includes the first imaging unit and the second imaging unit, the light from the second illumination unit may be collimated light or light that converges on the other surface of the inspection object.

[0030] By adopting such a configuration, compared with the case where the light from the second illumination unit is diffused light, the luminance of the bright portion when a defect is displayed as a bright portion can be increased, and the detection accuracy of thin defects such as fibrous foreign matter can be increased.

[0031] Also, in the inspection apparatus of the second aspect, the imaging unit includes a first imaging unit that intersects a straight line that is parallel to the optical axis of the illumination unit and passes through the light-emitting surface of the light of the illumination unit and captures the light from the illumination unit that passes through the inspection object, and a second imaging unit that does not intersect the straight line and captures the light from the illumination unit that passes through the inspection object. The inspection unit may determine the presence or absence of the defect from the dark portion in the image captured by the first imaging unit and determine the presence or absence of the defect from the bright portion in the image captured by the second imaging unit.

[0032] In the inspection apparatus according to the second embodiment, as described above, the first imaging unit is parallel to the optical axis of the illumination unit and intersects with a straight line passing through the light emission surface of the illumination unit. Therefore, as described above, defects can be displayed as dark areas in the image captured by the first imaging unit of light from the illumination unit. Also, as described above, the second imaging unit is parallel to the optical axis of the illumination unit and does not intersect with a straight line passing through the light emission surface of the illumination unit. Therefore, as described above, defects can be displayed as bright areas in the image captured by the second imaging unit of light from the illumination unit. Consequently, even with an inspection apparatus of this configuration, it is possible to detect fine defects such as fibrous foreign matter.

[0033] Furthermore, the inspection apparatus of the second embodiment further comprises another illumination unit positioned on the other side of the object to be inspected with respect to the object to be inspected and irradiating the other side with light, and another imaging unit positioned on the one side of the object to be inspected with respect to the object to be inspected and imaging the light from the other illumination unit that passes through the object to be inspected, and the inspection unit may determine whether or not there are defects on the one side and the other side of the object to be inspected based on the image captured by the imaging unit and the image captured by the other imaging unit. [Brief explanation of the drawing]

[0034] [Figure 1] This figure schematically shows an inspection apparatus in a first embodiment as a first aspect of the present invention. [Figure 2] This is a view of the inspection device shown in Figure 1, from the downstream side in the first transport direction. [Figure 3] This diagram schematically shows a portion of an example of an image captured by the imaging unit. [Figure 4] This is a diagram illustrating the propagation of light from a lighting unit. [Figure 5] This figure shows an inspection apparatus in a second embodiment as a first aspect of the present invention, similar to Figure 1. [Figure 6] This diagram schematically shows a portion of an example of an image of light from the second illumination unit captured by the imaging unit. [Figure 7] This figure shows an inspection apparatus in a third embodiment as a first aspect of the present invention, similar to Figure 1. [Figure 8] This figure shows an inspection apparatus in the fourth embodiment as a first aspect of the present invention, similar to Figure 1. [Figure 9] This figure schematically shows an inspection apparatus according to a fifth embodiment, which is a second aspect of the present invention. [Figure 10] This is a view of the inspection device shown in Figure 9 from the downstream side in the first transport direction. [Figure 11] This figure shows an inspection apparatus in a sixth embodiment, which is a second aspect of the present invention, similar to Figure 9. [Figure 12] This figure shows an inspection apparatus in the seventh embodiment, which is a second aspect of the present invention, similar to Figure 9. [Figure 13] This figure shows an inspection apparatus in the eighth embodiment, which is a second aspect of the present invention, similar to Figure 9. [Figure 14] This figure shows an inspection apparatus in the ninth embodiment, which is a second aspect of the present invention, similar to Figure 9. [Modes for carrying out the invention]

[0035] The following examples illustrate embodiments for implementing the inspection apparatus according to the present invention, along with the accompanying drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved from the following embodiments without departing from its spirit. In addition, in the drawings referenced below, the dimensions of each component may be shown differently or reference numerals may be omitted to facilitate understanding.

[0036] (First Embodiment) A first embodiment of the present invention will be described. Figure 1 is a schematic diagram showing the inspection apparatus in this embodiment. As shown in Figure 1, the inspection apparatus 1 of this embodiment mainly comprises a transport device 10, a lighting unit 21, an imaging unit 30, an inspection unit 40, a display unit 50, and a control unit CO. The object to be inspected 60 by the inspection apparatus 1 of this embodiment is a light-transmitting outer cover of a vehicle light fixture. The inspection apparatus 1 inspects the surface of the object to be inspected 60 for defects, such as the presence or absence of foreign matter adhering to the surface. For ease of understanding, the object to be inspected 60 is shown in a vertical cross-section in Figure 1.

[0037] The object to be inspected 60 in this embodiment, which is the outer cover, is a translucent plate-shaped member that curves convexly toward one side 60S1. A translucent rib 61 is provided on the outer periphery of the object to be inspected 60, projecting toward the other side 60S2, and the rib 61 extends around the entire circumference of the outer periphery of the object to be inspected 60. This object to be inspected 60 includes a hard coat layer (not shown) provided on one side 60S1 and an anti-fog coat layer (not shown) provided on the other side 60S2. The outer surface of this hard coat layer is one side 60S1 of the object to be inspected 60, and the outer surface of this anti-fog coat layer is the other side 60S2 of the object to be inspected 60. For example, when forming the hard coat layer and the anti-fog coat layer, foreign matter such as dust may adhere to these layers, and this foreign matter may become a defect on the surface of the object to be inspected 60. Such an object to be inspected 60 can be understood to include one surface 60S1 that is translucent and curves in a convex shape, and another surface 60S2 that is opposite to the first surface 60S1 and curves in a concave shape. The inspection device 1 of this embodiment inspects whether there are any defects on the first surface 60S1 and the other surface 60S2 of the object to be inspected 60.

[0038] The control unit CO consists of, for example, integrated circuits such as microcontrollers, ICs (Integrated Circuits), LSIs (Large-scale Integrated Circuits), and ASICs (Application Specific Integrated Circuits), as well as NC (Numerical Control) devices. Furthermore, when an NC device is used, the control unit CO may or may not use a machine learning machine. As described below, several components of the inspection device 1 are controlled by the control unit CO.

[0039] The conveying device 10 is a device that conveys the object to be inspected 60 in a predetermined direction. The conveying device 10 of this embodiment comprises a roller 11, a roller 12, and a transparent, strip-shaped support film 13. The rollers 11 and 12 are arranged at a predetermined distance from each other in a generally horizontal direction. One end of the support film 13 is wound around one roller 11, and the other end of the support film 13 is wound around the other roller 12, and a predetermined tension is applied to the support film 13 between the rollers 11 and 12. The object to be inspected 60 is placed on the support film 13 between the rollers 11 and 12 such that it is located on the roller 11 side of the illumination unit 21 and imaging unit 30, which will be described later. In this embodiment, the object to be inspected 60 is placed so that the ends of the ribs 61 of the object to be inspected 60 are in contact with the support film 13, and in the vertical direction, one surface 60S1 of the object to be inspected 60 is located on the opposite side from the support film 13 side from the other surface 60S2. As the rollers 11 and 12 rotate, the object to be inspected 60, which is placed on the support film 13 in this manner, is transported in a generally horizontal direction from one roller 11 side to the other roller 12 side, which is the first transport direction D1. The rotation speed and direction of the rollers 11 and 12 are adjusted by a control signal from the control unit CO. Therefore, the transport device 10 can transport the object to be inspected 60 in a second transport direction D2, which is opposite to the first transport direction D1, by reversing the rotation direction of the rollers 11 and 12. The support film 13 can be made of, for example, a resin film. The transport device 10 only needs to be able to transport the object to be inspected 60 in a predetermined direction, and the configuration of the transport device 10 is not particularly limited. For example, the transport device 10 may consist of a translucent jig that supports the object to be inspected 60 and a transport mechanism that transports the jig. In this case, the transport mechanism may include two linear actuators that are arranged to extend generally parallel to one side and the other side with respect to the jig. Furthermore, the transport mechanism may be a robotic arm, in which case the robotic arm may support the object to be inspected 60.

[0040] In this embodiment, the lighting unit 21 is positioned below the support film 13 between the rollers 11 and 12. The lighting unit 21 irradiates light L1 onto the other side 60S2 of the object to be inspected 60 being transported by the transport device 10 via the support film 13. In other words, the lighting unit 21 is positioned on the other side 60S2 of the object to be inspected 60 and irradiates this other side 60S2 with light L1. Figure 2 is a view of the inspection device 1 of Figure 1 from the downstream side of the first transport direction D1. For ease of understanding, in Figure 2, the object to be inspected 60 is shown as a vertical cross-section. Also in Figure 2, the light L1 emitted from the lighting unit 21 is shown as a dashed line. As shown in Figure 2, the lighting unit 21 of this embodiment is a single line illumination composed of multiple LEDs arranged in parallel in a direction that is roughly perpendicular and roughly horizontal to the first transport direction D1. Furthermore, as shown in Figure 1, the straight line 21a, which is parallel to the optical axis of the lighting unit 21 and passes through the light emission surface 21e of the lighting unit 21, is approximately parallel to the vertical, and the light L1 emitted from the lighting unit 21 is white. Note that the straight line 21a may not be parallel to the vertical direction. As described above, the object to be inspected 60 is translucent, so the light L1 emitted from the lighting unit 21 passes through the object to be inspected 60 from the other surface 60S2 to the one surface 60S1. As described above, the lighting unit 21 is line lighting, so the portion of the object to be inspected 60 through which the light L1 from the lighting unit 21 passes is in the shape of a line extending in a direction approximately perpendicular to the first transport direction D1. The lighting unit 21 switches between emitting and not emitting light based on a control signal from the control unit CO.

[0041] In this embodiment, the imaging unit 30 is positioned above the object under inspection 60 and captures the light L1 from the illumination unit 21 that passes through the object under inspection 60. In other words, the imaging unit 30 is positioned on one side 60S1 of the object under inspection 60 and captures the light L1 from the illumination unit 21 that passes through the object under inspection 60. In this embodiment, the imaging unit 30 is a line sensor camera and is positioned approximately directly above the illumination unit 21 and intersects with the line 21a described above. The imaging unit 30 is positioned such that its imaging range extends in a direction approximately perpendicular to the first transport direction D1 and that the imaging range is located in or near the portion of the object under inspection 60 through which the light L1 from the illumination unit 21 passes. The control unit CO controls the imaging unit 30 to capture the light passing through the object under inspection 60 being transported to the imaging unit 30 at predetermined time intervals and to output a two-dimensional image including the entirety of one side 60S1 of the object under inspection 60 to the inspection unit 40. Furthermore, the control unit CO controls the illumination unit 21 to prevent it from emitting light L1. The imaging unit 30 may output one-dimensional images captured at predetermined time intervals to the inspection unit 40. In this case, the inspection unit 40, which will be described later, generates a two-dimensional image containing the entirety of one of the surfaces 60S1 from the multiple one-dimensional images input to the inspection unit 40.

[0042] In this embodiment, the inspection unit 40 determines the presence or absence of defects on one surface 60S1 and the other surface 60S2 of the object to be inspected 60 based on a two-dimensional image input from the imaging unit 30. The determination by the inspection unit 40 means changing the signal output from the inspection unit 40 to the control unit CO based on the two-dimensional image. The specific determination by the inspection unit 40 will be described later. For example, the configuration of such an inspection unit 40 may be the same as that of the control unit CO.

[0043] The display unit 50 displays the inspection results based on the inspection unit 40's determination of whether or not there are defects. An example of the display unit 50 is a liquid crystal display.

[0044] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0045] First, the object to be inspected 60 is placed on a support film 13 between rollers 11 and 12 of the transport device 10, so as to be located on the roller 11 side of the illumination unit 21 and imaging unit 30. The control unit CO controls the illumination unit 21 to emit light L1. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the illumination unit 21 irradiates the other side 60S2 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10 with light L1 via the support film 13. The control unit CO controls the imaging unit 30 to capture the light L1 from the illumination unit 21 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0046] Here, if there is a defect such as a foreign object on one surface 60S1 or the other surface 60S2 of the object under inspection 60, much of the light L1 irradiated onto the object under inspection 60 by the illumination unit 21 that is incident on the defect is absorbed or reflected by the defect and does not enter the imaging unit 30. On the other hand, much of the light that does not enter on the defect passes through the object under inspection 60 from the other surface 60S2 to the one surface 60S1 and enters the imaging unit 30. For this reason, as shown in Figure 3, the defect may be displayed as a dark area 72 surrounded by a bright area 71 in the image of the light L1 from the illumination unit 21 captured by the imaging unit 30. Figure 3 is a schematic diagram showing a part of an example of an image captured by the imaging unit 30. In Figure 3, the dark area 72 is hatched.

[0047] In this embodiment, the inspection unit 40 extracts areas in the image captured by the imaging unit 30 where the brightness value is lower than a predetermined threshold, and calculates the area of ​​the extracted areas. If at least one of the calculated areas is larger than the predetermined area, it outputs a signal to the control unit CO indicating that there is a defect. On the other hand, if all of the calculated areas are smaller than the predetermined area, or if no areas are extracted, the inspection unit 40 outputs a signal to the control unit CO indicating that there is no defect. In this way, the inspection unit 40 determines whether or not there is a defect on one surface 60S1 and the other surface 60S2 of the object under inspection 60 based on the image captured by the imaging unit 30. Note that the inspection unit 40 only needs to be able to determine whether or not there is a defect on one surface 60S1 and the other surface 60S2 of the object under inspection 60 based on the image captured by the imaging unit 30. For example, the inspection unit 40 may perform a binarization process on the two-dimensional image input from the imaging unit 30 using a predetermined threshold, and extract areas in the binarized image where the brightness value is lower than the predetermined threshold. Furthermore, the inspection unit 40 may calculate the area of ​​the extracted region and the maximum width of the region, and if the calculated area is greater than a predetermined area and the calculated width is greater than a predetermined width, it may output a signal to the control unit CO indicating that there is a defect.

[0048] The control unit CO outputs a control signal to the display unit 50 corresponding to the signal input from the inspection unit 40, and displays the inspection result on the display unit 50. In this way, the inspection device 1 of this embodiment inspects for defects on one surface 60S1 and the other surface 60S2 of the object to be inspected 60. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, which is opposite to the first transport direction D1, and returns the object to be inspected 60 to the position in which it was placed on the transport device 10. As a result, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same. For example, an operator who places the object to be inspected 60 on the transport device 10 of the inspection device 1 can receive the object to be inspected 60 after inspection without moving. Note that the transport device 10 does not necessarily have to transport the object to be inspected 60 in the second transport direction D2.

[0049] Incidentally, the outer edge of the object under inspection 60, which is the outer cover, is provided with ribs 61 that protrude toward the other surface 60S2. Therefore, depending on the direction of light irradiation onto the object under inspection 60, the light may be reflected by the boundary between the ribs 61 and the other surface 60S2, or by the ribs 61, and this reflected light may appear in the image. When such reflected light appears in the image, it may become impossible to detect defects due to this light, or this light may be mistakenly detected as a defect, and the accuracy of defect detection tends to decrease.

[0050] Therefore, the inspection apparatus 1 of this embodiment comprises an illumination unit 21, an imaging unit 30, and an inspection unit 40. The illumination unit 21 is positioned on the side of the other surface 60S2 relative to the light-transmitting object 60 under inspection, which includes one convexly curved surface 60S1 and the other concavely curved surface 60S2 facing the first surface 60S1, and irradiates the other surface 60S2 with light L1. The imaging unit 30 is positioned on the side of the first surface 60S1 relative to the object under inspection 60 and captures the light L1 from the illumination unit 21 that passes through the object under inspection 60. The inspection unit 40 determines whether or not there are defects in the object under inspection 60 based on the image captured by the imaging unit 30. In the inspection apparatus 1 of this embodiment, the illumination unit 21 irradiates the other concavely curved surface 60S2 with light L1. In addition, the outer edge of the object under inspection 60 is provided with ribs 61 that protrude from this other surface 60S2. Therefore, as shown in Figure 4, some of the light L1 from the illumination unit 21 may be reflected at the boundary between the rib 61 and the other surface 60S2, or by the rib 61, and head toward the other surface 60S2. In this way, some of the light L1a that heads toward the other surface 60S2 is reflected by that other surface 60S2. In the inspection apparatus 1 of this embodiment, as described above, the imaging unit 30 is positioned on the side of one surface 60S1 with respect to the object to be inspected 60, so that the light reflected by the other surface 60S2 in this way does not enter the imaging unit 30. In addition, another portion of the light L1a that heads toward the other surface 60S2 enters the object to be inspected 60 from the other surface 60S2 and exits from the one surface 60S1. In the inspection apparatus 1 of this embodiment, as described above, one surface 60S1 is curved in a convex shape, so that the light incident on the object to be inspected 60 from the other surface 60S2 can be emitted from the one surface 60S1 in a diffuse manner, and this light is suppressed from being incident on the imaging unit 30. For this reason, the light emitted from the illumination unit 21 and reflected at the boundary between the rib 61 and the other surface 60S2, or at the rib 61, is less likely to be captured in the image taken by the imaging unit 30. Accordingly, even when the rib 61 protruding from the other surface 60S2 is provided on the outer edge of the object to be inspected 60, the inspection apparatus 1 of this embodiment can suppress a decrease in the detection accuracy of defects on the surface of the object to be inspected 60, whether it be one surface 60S1 or the other surface 60S2.

[0051] (Second Embodiment) Next, a second embodiment as a first aspect of the present invention will be described in detail with reference to Figure 5. Note that components identical or equivalent to those in the first embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0052] Figure 5 is a diagram showing an inspection apparatus in a second embodiment of the present invention, similar to Figure 1. As shown in Figure 5, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the first embodiment in that the lighting unit 21 has a first lighting section 23 and a second lighting section 25. In Figure 5, the light L3 emitted from the first lighting section 23 and the light L5 emitted from the second lighting section 25 are shown by dashed lines.

[0053] The first illumination unit 23 in this embodiment has the same configuration as the illumination unit 21 in the first embodiment. Therefore, the first illumination unit 23 in this embodiment is positioned below the support film 13 between the rollers 11 and 12 and is a line illumination consisting of a plurality of LEDs arranged in parallel in a direction that is generally perpendicular and generally horizontal to the first transport direction D1. Furthermore, the first straight line 23a, which is parallel to the optical axis of the first illumination unit 23 and passes through the light emission surface 23e of the first illumination unit 23, is generally parallel to the vertical, and the imaging unit 30 intersects this first straight line 23a. The first illumination unit 23 irradiates the other surface 60S2 of the object to be inspected 60 being transported by the transport device 10 with light L3 via the support film 13, and this light L3 passes through the object to be inspected 60 from the other surface 60S2 side toward the one surface 60S1 side. The portion of the object under inspection 60 through which light L3 from the first illumination unit 23 passes is in the shape of a line extending in a direction approximately perpendicular to the first transport direction D1.

[0054] On the other hand, the second illumination unit 25 of this embodiment is positioned below the support film 13 between the rollers 11 and 12, closer to the roller 11 than the first illumination unit 23. Similar to the first illumination unit 23, the second illumination unit 25 is a line illumination composed of multiple LEDs arranged in parallel in a direction that is roughly perpendicular and roughly horizontal to the first transport direction D1. The second straight line 25a, which is parallel to the optical axis of the second illumination unit 25 and passes through the light emission surface 25e of the second illumination unit 25, extends in the vertical direction, but is inclined upward toward the roller 12 and is not parallel to the first straight line 23a. This second straight line 25a passes between the imaging unit 30 and the roller 12 and does not intersect with the imaging unit 30. The second illumination unit 25 irradiates light L5 onto the other surface 60S2 of the object to be inspected 60, which is being transported by the transport device 10, via the support film 13. This light penetrates the object to be inspected 60 from the other surface 60S2 side toward the first surface 60S1 side. The portion of the object to be inspected 60 through which the light L5 from the second illumination unit 25 penetrates is in the shape of a line extending in a direction approximately perpendicular to the first transport direction D1, and overlaps with the portion of the object to be inspected 60 through which the light L3 from the first illumination unit 23 penetrates. The imaging range of the imaging unit 30 is located at or near the overlapping portion of the object to be inspected 60 where the portion through which the light L3 from the first illumination unit 23 penetrates and the portion through which the light L5 from the second illumination unit 25 penetrates. In other words, the first illumination unit 23, the second illumination unit 25, and the imaging unit 30 are arranged so that the imaging range of the imaging unit 30 is located in this manner.

[0055] Furthermore, when the first illumination unit 23 emits light L3, the illumination unit 21 does not emit light L5 from the second illumination unit 25, and when the second illumination unit 25 emits light L5, the illumination unit 23 does not emit light L3. In other words, the timing at which the first illumination unit 23 irradiates the other surface 60S2 of the object under inspection 60 with light L3 is different from the timing at which the second illumination unit 25 irradiates the other surface 60S2 of the object under inspection 60 with light L5.

[0056] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0057] In this embodiment, similar to the first embodiment, the object to be inspected 60 is placed on the support film 13 between the rollers 11 and 12 of the transport device 10 so that it is located on the roller 11 side of the illumination unit 21 and the imaging unit 30. The control unit CO controls the first illumination unit 23 to emit light L3 from the first illumination unit 23. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the first illumination unit 23 irradiates light onto the other side 60S2 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10 via the support film 13. At this time, light L5 from the second illumination unit 25 is not emitted. The control unit CO controls the imaging unit 30 to capture light L3 from the first illumination unit 23 that passes through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image that includes the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0058] In this embodiment, after the imaging unit 30 has finished imaging, the control unit CO controls the second illumination unit 25 to emit light L5. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, returning the object to be inspected 60 to the position where it was placed on the transport device 10. For this reason, the second illumination unit 25 irradiates the other side 60S2 of the object to be inspected 60 being transported in the second transport direction D2 by the transport device 10 with light L5 via the support film 13. At this time, light L3 from the first illumination unit 23 is not emitted. The control unit CO controls the imaging unit 30 to capture light L5 from the second illumination unit 25 that passes through the object to be inspected 60 being transported in the second transport direction D2 at predetermined time intervals, and outputs a two-dimensional image that includes the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0059] As described above, in this embodiment, the first straight line 23a and the second straight line 25a are non-parallel to each other. Therefore, the illumination unit 21 can be understood to have a first illumination unit 23 that irradiates the other surface 60S2 of the object under inspection 60 from a first direction, and a second illumination unit 25 that irradiates the other surface 60S2 of the object under inspection 60 from a second direction different from the first direction, with light L5. Furthermore, the imaging unit 30 can be understood to individually image the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 that are transmitted through the object under inspection 60.

[0060] In this embodiment, the inspection unit 40 determines the presence or absence of defects based on the image captured by the light L3 from the first illumination unit 23, and further determines the presence or absence of defects based on the image captured by the light L5 from the second illumination unit 25. Specifically, the inspection unit 40 determines the presence or absence of defects from the dark areas in the image captured by the light L3 from the first illumination unit 23. In this embodiment, the first straight line 23a intersects with the imaging unit 30. Therefore, similar to the first embodiment, defects can be displayed as dark areas in the image of the light L3 from the first illumination unit 23 captured by the imaging unit 30. In this embodiment, similar to the first embodiment, the inspection unit 40 extracts areas in the image of the light L3 from the first illumination unit 23 captured by the imaging unit 30 where the brightness value is lower than a predetermined threshold, and calculates the area of ​​the extracted area. Then, if the calculated area is larger than the predetermined area, it outputs a signal to the control unit CO indicating the presence of a defect.

[0061] On the other hand, the second straight line 25a does not intersect with the imaging unit 30. Therefore, compared to the case where the second straight line 25a intersects with the imaging unit 30, of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25, light that passes through the object under inspection 60 from the other surface 60S2 side to the one surface 60S1 side without incident on defects on one surface 60S1 and the other surface 60S2 of the object under inspection 60 is less likely to be incident on the imaging unit 30. In this embodiment, the position and orientation of the second illumination unit 25 relative to the imaging unit 30 are adjusted so that much of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that passes through the object under inspection 60 in this way does not occur on the imaging unit 30. On the other hand, of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that is incident on defects is absorbed or reflected by the defects. Therefore, the light that is reflected by the defects and also passes through the object under inspection 60 can occur on the imaging unit 30. Therefore, as shown in Figure 6, defects may appear as bright areas 71 surrounded by dark areas 72 in the image of light L5 from the second illumination unit 25 captured by the imaging unit 30. Figure 6 is a schematic diagram showing a part of an example of an image of light L5 from the second illumination unit 25 captured by the imaging unit 30. In Figure 6, hatching is applied to the dark areas 72. The inspection unit 40 of this embodiment extracts areas in the image of light L5 from the second illumination unit 25 captured by the imaging unit 30 where the brightness value is higher than a predetermined threshold, and calculates the area of ​​the extracted areas. If at least one of the calculated areas is larger than a predetermined area, it outputs a signal to the control unit CO indicating that there is a defect.

[0062] Furthermore, if the area of ​​all regions extracted in the image of light L3 from the first illumination unit 23 captured by the imaging unit 30 is smaller than a predetermined area or no region is extracted, and if the area of ​​all regions extracted in the image of light L5 from the second illumination unit 25 captured by the imaging unit 30 is larger than a predetermined area or no region is extracted, the inspection unit 40 outputs a signal to the control unit CO indicating that there are no defects. In this way, the inspection unit 40 determines the presence or absence of defects based on the image captured of light L3 from the first illumination unit 23, and further determines the presence or absence of defects based on the image captured of light L5 from the second illumination unit 25. However, it is sufficient for the inspection unit 40 to determine the presence or absence of defects based on the image captured of light L3 from the first illumination unit 23, and further determines the presence or absence of defects based on the image captured of light L5 from the second illumination unit 25. For example, when the inspection unit 40 determines whether or not there is a defect based on the image captured by the light L5 from the second illumination unit 25, it may perform a binarization process on the two-dimensional image input from the imaging unit 30 using a predetermined threshold, and extract areas in the binarized image where the brightness value is higher than the predetermined threshold. Alternatively, when the inspection unit 40 determines whether or not there is a defect based on the image captured by the light L5 from the second illumination unit 25, it may calculate the area of ​​the extracted area and the maximum width of the area, and output a signal to the control unit CO indicating the presence of a defect if the calculated area is greater than a predetermined area and the calculated width is greater than a predetermined width.

[0063] The control unit CO outputs a control signal to the display unit 50 corresponding to the signal input from the inspection unit 40, and displays the inspection result on the display unit 50. As described above, the object to be inspected 60 is returned to the position in which it was placed on the transport device 10. Therefore, similar to the first embodiment, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same.

[0064] As described above, in the inspection apparatus 1 of this embodiment, the illumination unit 21 has a first illumination unit 23 that irradiates the other surface 60S2 of the object to be inspected 60 with light L3 from a first direction, and a second illumination unit 25 that irradiates the other surface 60S2 of the object to be inspected 60 with light L5 from a second direction different from the first direction. The imaging unit 30 separately images the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 that are transmitted through the object to be inspected 60. The imaging unit 30 intersects with the first straight line 23a but does not intersect with the second straight line 25a. The inspection unit 40 determines the presence or absence of defects from the dark areas 72 in the image captured with light L3 from the first illumination unit 23, and from the bright areas 71 in the image captured with light L5 from the second illumination unit 25. Incidentally, because light propagates while diffusing, if the defect is thin and fibrous, such as a strand of hair or thread, such a defect tends not to be easily displayed as a dark area 72 in the image captured by the light L3 from the first illumination unit 23. However, in the inspection device 1 of this embodiment, such defects can be displayed as bright areas 71 in the image captured by the light L5 from the second illumination unit 25. Therefore, the inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign objects.

[0065] Furthermore, in the inspection apparatus 1 of this embodiment, the timing of when the first illumination unit 23 irradiates light L3 onto the other surface 60S2 of the object to be inspected 60 and the timing of when the second illumination unit 25 irradiates light L5 onto the other surface 60S2 of the object to be inspected 60 are different. Therefore, the light L5 from the second illumination unit 25 does not appear in the image captured by the light L3 from the first illumination unit 23. Similarly, the light L3 from the first illumination unit 23 does not appear in the image captured by the light L5 from the second illumination unit 25. For this reason, the imaging unit 30 can capture the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 individually, even if it does not have, for example, a first imaging unit that captures the light L3 from the first illumination unit 23 and a second imaging unit that captures the light L5 from the second illumination unit 25.

[0066] Furthermore, from the viewpoint of increasing the detection accuracy of fine defects such as fibrous foreign matter, it is preferable that the light L5 from the second illumination unit 25 is collimated light or light focused on the other surface 60S2 of the object under inspection 60. With this configuration, compared to the case where the light L5 from the second illumination unit 25 is diffuse light, the brightness of the bright area 71 when the defect is displayed as a bright area 71 can be increased, thereby increasing the detection accuracy of fine defects such as fibrous foreign matter.

[0067] (Third embodiment) Next, a third embodiment as a first aspect of the present invention will be described in detail with reference to Figure 7. Note that components identical or equivalent to those in the second embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0068] Figure 7 is a diagram showing an inspection apparatus in a third embodiment of the present invention, similar to Figure 1. As shown in Figure 7, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the second embodiment in that the second illumination unit 25 is located downstream of the first illumination unit 23 in the first transport direction D1, and the imaging unit 30 has a first imaging unit 31 and a second imaging unit 32.

[0069] The second illumination unit 25 in this embodiment has the same configuration as the second illumination unit 25 in the second embodiment. However, as described above, the second illumination unit 25 is located downstream of the first illumination unit 23 in the first transport direction D1.

[0070] The first imaging unit 31 in this embodiment has the same configuration as the imaging unit 30 in the second embodiment. Therefore, the first imaging unit 31 in this embodiment is a line sensor camera, located approximately directly above the first illumination unit 23, and intersects with the first straight line 23a. The first imaging unit 31 is positioned such that its imaging range extends in a direction approximately perpendicular to the first transport direction D1, and that the imaging range is located in or near a portion of the object under inspection 60 through which light L3 from the first illumination unit 23 passes. The first imaging unit 31 then images the light L3 from the first illumination unit 23 that passes through the object under inspection 60.

[0071] The second imaging unit 32 in this embodiment is a line sensor camera, similar to the first imaging unit 31. The second imaging unit 32 is located above the object to be inspected 60 and in a direction parallel to the first transport direction D1, on the roller 12 side of the first illumination unit 23 and the first imaging unit 31, and does not intersect with the first straight line 23a and the second straight line 25a. The second imaging unit 32 is positioned such that its imaging range extends in a direction generally perpendicular to the first transport direction D1, and that this imaging range is located in or near the portion of the object to be inspected 60 through which light L5 from the second illumination unit 25 passes. The second imaging unit 32 then images the light L5 from the second illumination unit 25 that passes through the object to be inspected 60.

[0072] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0073] In this embodiment, similar to the second embodiment, the object to be inspected 60 is placed on the support film 13 between the rollers 11 and 12 of the transport device 10 so that it is located on the roller 11 side of the illumination unit 21 and the imaging unit 30. The control unit CO controls the first illumination unit 23 to emit light L3 from the first illumination unit 23. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the first illumination unit 23 irradiates the other side 60S2 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10 with light L3 via the support film 13. At this time, light L5 from the second illumination unit 25 is not emitted. The control unit CO controls the first imaging unit 31 to capture light L3 from the first illumination unit 23 that passes through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image that includes the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0074] Furthermore, similar to the second embodiment, the control unit CO controls the second illumination unit 25 to emit light L5 after the imaging by the first imaging unit 31 is completed. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, returning the object to be inspected 60 to the position where it was placed on the transport device 10. For this reason, the second illumination unit 25 irradiates light L5 onto the other side 60S2 of the object to be inspected 60 being transported in the second transport direction D2 by the transport device 10 via the support film 13. At this time, light L3 from the first illumination unit 23 is not emitted. The control unit CO controls the second imaging unit 32 to capture light L5 from the second illumination unit 25 that passes through the object to be inspected 60 being transported in the second transport direction D2 at predetermined time intervals, and outputs a two-dimensional image that includes the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0075] In other words, in this embodiment, the first imaging unit 31 captures the light L3 from the first illumination unit 23 that passes through the object to be inspected 60, and the second imaging unit 32 captures the light L5 from the second illumination unit 25 that passes through the object to be inspected 60.

[0076] In this embodiment, the first straight line 23a intersects with the first imaging unit 31. Therefore, similar to the second embodiment, defects in the object under inspection 60 may appear as dark areas in the image of light L3 from the first illumination unit 23 captured by the first imaging unit 31. Also, the second straight line 25a does not intersect with the second imaging unit 32. In this embodiment, similar to the second embodiment, the position and orientation of the second illumination unit 25 relative to the second imaging unit 32 are adjusted so that much of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that passes through the object under inspection 60 without entering defects in the object under inspection 60 does not enter the second imaging unit 32. Therefore, defects may appear as bright areas surrounded by dark areas in the image of light L5 from the second illumination unit 25 captured by the second imaging unit 32.

[0077] In this embodiment, the inspection unit 40, similar to the second embodiment, determines the presence or absence of defects from the dark areas in the image of light L3 from the first illumination unit 23 captured by the first imaging unit 31, and further determines the presence or absence of defects from the bright areas in the image of light L5 from the second illumination unit 25 captured by the second imaging unit 32.

[0078] Similar to the second embodiment, the control unit CO outputs a control signal corresponding to the signal input from the inspection unit 40 to the display unit 50, and displays the inspection result on the display unit 50. As described above, the object to be inspected 60 is returned to the position where it was placed on the transport device 10. Therefore, similar to the first embodiment, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same.

[0079] The inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign matter, in the same manner as in the second embodiment.

[0080] Furthermore, in the inspection apparatus 1 of this embodiment, the imaging unit 30 has a first imaging unit 31 that images light L3 from a first illumination unit 23 that passes through the object to be inspected 60, and a second imaging unit 32 that images light L5 from a second illumination unit 25 that passes through the object to be inspected 60. Therefore, with the inspection apparatus 1 of this embodiment, compared to the case where the imaging unit 30 does not have a second imaging unit 32, the degree of freedom of the position and orientation of the second illumination unit 25 relative to the object to be inspected 60 can be improved, and defects can be more easily displayed in the image captured by the light L5 from the second illumination unit 25 that passes through the object to be inspected 60. For this reason, the inspection apparatus 1 of this embodiment can further suppress a decrease in the detection accuracy of defects in the object to be inspected 60.

[0081] (Fourth Embodiment) Next, a fourth embodiment, as a first aspect of the present invention, will be described in detail with reference to Figure 8. Note that components identical or equivalent to those in the third embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0082] Figure 8 is a diagram showing an inspection apparatus in the fourth embodiment of the present invention, similar to Figure 1. As shown in Figure 8, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the third embodiment in that the lighting unit 21 consists of a single lighting section, and the second imaging section 32 is tilted with respect to the vertical direction.

[0083] The lighting unit 21 of this embodiment has the same configuration as the lighting unit 21 of the first embodiment. Therefore, the lighting unit 21 of this embodiment is positioned below the support film 13 between the rollers 11 and 12 and is a line illumination consisting of a plurality of LEDs arranged in parallel in a direction that is generally perpendicular and generally horizontal to the first transport direction D1. Furthermore, the straight line 21a that is parallel to the optical axis of the lighting unit 21 and passes through the emission surface 21e of the lighting unit 21 is generally parallel to the vertical, the first imaging unit 31 intersects this straight line 21a, and the second imaging unit 32 does not intersect this straight line 21a. The portion of the object under inspection 60 through which the light L1 from the lighting unit 21 is transmitted is a line extending in a direction that is generally perpendicular to the first transport direction D1. The imaging range of the first imaging unit 31 is located in the portion of the object under inspection 60 through which the light L1 from the lighting unit 21 is transmitted, or in the vicinity of such portion.

[0084] As described above, the second imaging unit 32 of this embodiment is tilted with respect to the vertical direction. Specifically, the second imaging unit 32 is tilted with respect to the vertical direction such that the imaging range extends in a direction approximately perpendicular to the first transport direction D1 and that the imaging range is located in or near the area of ​​the object under inspection 60 through which light L1 from the illumination unit 21 passes. In other words, the second imaging unit 32 is positioned such that the imaging range is located in this manner.

[0085] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0086] In this embodiment, similar to the third embodiment, the object to be inspected 60 is placed on the support film 13 between the rollers 11 and 12 of the transport device 10 so that it is positioned on the roller 11 side of the illumination unit 21 and the imaging unit 30. The control unit CO controls the illumination unit 21 to emit light L1. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the illumination unit 21 irradiates light onto the other side 60S2 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10 via the support film 13. The control unit CO controls the first imaging unit 31 and the second imaging unit 32 to capture images of the light L1 from the illumination unit 21 that passes through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image containing the entirety of one side 60S1 of the object to be inspected 60 to the inspection unit 40.

[0087] In other words, in this embodiment, the first imaging unit 31 intersecting the straight line 21a and the second imaging unit 32 not intersecting the straight line 21a each capture light L1 from the illumination unit 21 that passes through the object to be inspected 60.

[0088] In this embodiment, as described above, the first imaging unit 31 intersects with the straight line 21a, so, similar to the third embodiment, defects in the object under inspection 60 may be displayed as dark areas in the image of the light L1 from the illumination unit 21 captured by the first imaging unit 31. Also, the straight line 21a does not intersect with the second imaging unit 32. In this embodiment, similar to the third embodiment, the position and orientation of the second imaging unit 32 relative to the illumination unit 21 are adjusted so that much of the light L1 irradiated onto the object under inspection 60 by the illumination unit 21 that passes through the object under inspection 60 without entering defects in the object under inspection 60 does not enter the second imaging unit 32. For this reason, defects may be displayed as bright areas surrounded by dark areas in the image of the light L1 from the illumination unit 21 captured by the second imaging unit 32.

[0089] In this embodiment, the inspection unit 40, similar to the third embodiment, determines the presence or absence of defects from the dark areas in the image of the light L1 from the illumination unit 21 captured by the first imaging unit 31, and further determines the presence or absence of defects from the bright areas in the image of the light L1 from the illumination unit 21 captured by the second imaging unit 32.

[0090] Similar to the third embodiment, the control unit CO outputs a control signal to the display unit 50 corresponding to the signal input from the inspection unit 40, and displays the inspection result on the display unit 50. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, which is opposite to the first transport direction D1, and returns the object to be inspected 60 to the position in which it was placed on the transport device 10. As a result, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same. Note that the control unit CO does not have to transport the object to be inspected 60 in the second transport direction D2 by the transport device 10.

[0091] The inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign matter, in the same manner as in the third embodiment.

[0092] Furthermore, in the inspection apparatus 1 of this embodiment, the imaging unit 30 has a first imaging unit 31 that images light L3 from a first illumination unit 23 that passes through the object to be inspected 60, and a second imaging unit 32 that images light L5 from a second illumination unit 25 that passes through the object to be inspected 60. Therefore, with the inspection apparatus 1 of this embodiment, compared to the case where the imaging unit 30 does not have a second imaging unit 32, the degree of freedom of the position and orientation of the second illumination unit 25 relative to the object to be inspected 60 can be improved, and defects can be more easily displayed in the image captured by the light L5 from the second illumination unit 25 that passes through the object to be inspected 60. For this reason, the inspection apparatus 1 of this embodiment can further suppress a decrease in the detection accuracy of defects in the object to be inspected 60.

[0093] (Fifth embodiment) Next, a fifth embodiment, which is a second aspect of the present invention, will be described. Note that components identical or equivalent to those in the first embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions will be omitted.

[0094] Figure 9 is a schematic diagram showing the inspection apparatus in this embodiment. As shown in Figure 9, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the first embodiment in that the lighting unit 21 is positioned above the support film 13 between the rollers 11 and 12, and the imaging unit 30 is positioned below the support film 13 between the rollers 11 and 12.

[0095] In this embodiment, the lighting unit 21 irradiates light L1 onto one side 60S1 of the object to be inspected 60 being transported by the transport device 10. In other words, the lighting unit 21 is positioned on one side 60S1 of the object to be inspected 60 and irradiates this side 60S1 with light L1. Figure 10 is a view of the inspection device 1 of Figure 9 from the downstream side in the first transport direction D1. For ease of understanding, the object to be inspected 60 is shown as a vertical cross-section in Figure 10. Also in Figure 10, the light L1 emitted from the lighting unit 21 is shown as a dashed line. As shown in Figure 10, the light L1 passes through the object to be inspected 60 from one side 60S1 to the other side 60S2.

[0096] In this embodiment, the imaging unit 30 images the light L1 from the illumination unit 21 that passes through the object under inspection 60 via the support film 13. In other words, the imaging unit 30 is positioned on the other side 60S2 of the object under inspection 60 and images the light L1 from the illumination unit 21 that passes through the object under inspection 60. In this embodiment, the imaging unit 30 is a line sensor camera and is located approximately directly below the illumination unit 21 and intersects with the straight line 21a. The imaging unit 30 is positioned such that its imaging range extends in a direction approximately perpendicular to the first transport direction D1 and that the imaging range is located in the portion of the object under inspection 60 through which the light L1 from the illumination unit 21 passes or in the vicinity of such portion. The control unit CO controls the imaging unit 30 to image the light passing through the object under inspection 60 being transported to the imaging unit 30 at predetermined time intervals and to output a two-dimensional image including the entire other side 60S2 of the object under inspection 60 to the inspection unit 40.

[0097] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0098] In this embodiment, similar to the first embodiment, the object to be inspected 60 is placed on a support film 13 between rollers 11 and 12 of the transport device 10 so as to be located on the roller 11 side of the illumination unit 21 and imaging unit 30. The control unit CO controls the illumination unit 21 to emit light L1. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the illumination unit 21 irradiates light L1 onto one side 60S1 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10. The control unit CO controls the imaging unit 30 to image the light L1 from the illumination unit 21 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0099] If there is a defect such as a foreign object on one surface 60S1 or the other surface 60S2 of the object to be inspected 60, as in the first embodiment, the defect may be displayed as a dark area 72 surrounded by a bright area 71 in the image of the light from the illumination unit 21 captured by the imaging unit 30, as shown in Figure 3.

[0100] In this embodiment, the inspection unit 40 determines whether or not there are defects on one surface 60S1 and the other surface 60S2 of the object to be inspected 60, based on the image captured by the imaging unit 30, in the same manner as in the first embodiment.

[0101] The control unit CO outputs a control signal to the display unit 50 in accordance with the signal input from the inspection unit 40, and displays the inspection results on the display unit 50. The control unit CO also controls the transport device 10 to return the object to be inspected 60 to the position in which the object to be inspected 60 was placed on the transport device 10.

[0102] Incidentally, the outer edge of the object under inspection 60, which is the outer cover, is provided with ribs 61 that protrude toward the other surface 60S2. As a result, some of the light from the illumination unit 21 may enter the ribs 61 and be emitted from the ribs 61 toward the imaging unit 30, or reflected toward the imaging unit 30 by the ribs 61. In other words, light transmitted through the ribs 61 or light reflected by the ribs 61 may be captured in the image taken by the imaging unit 30. If such light from the ribs 61 overlaps with a part of the object under inspection 60 corresponding to surface 60S1 or surface 60S2, it may become impossible to properly inspect for defects in that part due to the light from the ribs 61, and in this case, there is a concern that the inspection range for defects on the surface of the object under inspection will be narrowed.

[0103] Therefore, the inspection apparatus 1 of this embodiment comprises an illumination unit 21, an imaging unit 30, and an inspection unit 40. The illumination unit 21 is positioned on the side of the translucent object to be inspected 60, which includes one convexly curved surface 60S1 and the other concavely curved surface 60S2 facing the first surface 60S1, and irradiates the first surface 60S1 with light L1. The imaging unit 30 is positioned on the side of the other surface 60S2 with respect to the object to be inspected 60 and captures the light L1 from the illumination unit 21 that passes through the object to be inspected 60. The inspection unit 40 determines whether or not there are defects in the object to be inspected 60 based on the image captured by the imaging unit 30. In the inspection apparatus 1 of this embodiment, the imaging unit 30 is positioned on the side of the other surface 60S2 with respect to the object to be inspected 60. In addition, a rib 61 is provided on the outer edge of the object to be inspected 60 that protrudes from this other surface 60S2. Of the light L1 from the illumination unit 21, some of the light that enters the object under inspection 60 from one surface 60S1, and some of the light that enters the object under inspection 60 from one surface 60S1 and exits from the other surface 60S2 of the object under inspection 60, may enter the rib 61 or be reflected by the rib 61 and head towards the imaging unit 30. Even if light heads towards the imaging unit 30 from the rib 61 in this way, this light tends to head towards the imaging unit 30 without passing through the other surface 60S2 or one surface 60S1 in the vicinity of the rib 61. On the other hand, unlike in this embodiment, if the illumination unit 21 is positioned on the other surface 60S2 side with respect to the object under inspection 60, and the imaging unit 30 is positioned on the one surface 60S1 side with respect to the object under inspection 60, then the light L1 from the illumination unit 21 that heads towards the imaging unit from the rib 61 tends to head towards the imaging unit 30 via the other surface 60S2 or one surface 60S1 in the vicinity of the rib 61. In this case, much of the light from the rib 61 heading towards the imaging unit 30 is likely to overlap with the light heading towards the imaging unit 30 via the other surface 60S2 or the other surface 60S1 in the vicinity of the rib 61, without passing through the rib 61, and thus easily enter the imaging unit 30. In other words, in the image captured by the imaging unit 30, the light from the rib 61 is likely to overlap with the other surface 60S2 or the other surface 60S1 in the vicinity of the rib 61.Therefore, the light directed from the rib 61 towards the imaging unit 30 tends to prevent proper detection of defects on the other surface 60S2 or the other surface 60S1 near the rib 61. Accordingly, the inspection device 1 of this embodiment, compared to the case where the illumination unit 21 is positioned on the other surface 60S2 side with respect to the object under inspection 60 and the imaging unit 30 is positioned on the one surface 60S1 side with respect to the object under inspection 60, is less likely to overlap with the light directed from the rib 61 towards the imaging unit 30, even if the light is directed from the rib 61 towards the imaging unit 30, as the light is directed towards the other surface 60S2 or the other surface 60S1 near the rib 61 without passing through the rib 61. Therefore, the inspection device 1 of this embodiment can suppress the inability to properly detect defects on the other surface 60S2 or the other surface 60S1 near the rib 61. Therefore, even if the inspection device 1 of this embodiment is provided with a rib 61 protruding from the other surface 60S2 on the outer edge of the object to be inspected 60, and light is directed from the rib 61 towards the imaging unit 30, it is possible to suppress the narrowing of the inspection range for surface defects of the object to be inspected 60.

[0104] (Sixth Embodiment) Next, a sixth embodiment, which is a second aspect of the present invention, will be described in detail with reference to Figure 11. Note that components identical or equivalent to those in the fifth embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0105] Figure 11 is a diagram showing the inspection apparatus in this embodiment, similar to Figure 9. As shown in Figure 11, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the fifth embodiment in that the lighting unit 21 has a first lighting section 23 and a second lighting section 25. In Figure 11, the light L3 emitted from the first lighting section 23 and the light L5 emitted from the second lighting section 25 are shown by dashed lines.

[0106] In this embodiment, the first illumination unit 23 has the same configuration as the illumination unit 21 of the fifth embodiment. Therefore, the first illumination unit 23 in this embodiment is positioned above the object to be inspected 60 and is a line illumination consisting of a plurality of LEDs arranged in parallel in a direction that is generally perpendicular and generally horizontal to the first transport direction D1. Furthermore, the first straight line 23a, which is parallel to the optical axis of the first illumination unit 23 and passes through the light emission surface 23e of the first illumination unit 23, is generally parallel to the vertical, and the imaging unit 30 intersects this first straight line 23a. The first illumination unit 23 irradiates light L3 onto one surface 60S1 of the object to be inspected 60 that is transported by the transport device 10, and this light L3 passes through the object to be inspected 60 from the one surface 60S1 side to the other surface 60S2 side. The portion of the object under inspection 60 through which light L3 from the first illumination unit 23 passes is in the shape of a line extending in a direction approximately perpendicular to the first transport direction D1.

[0107] On the other hand, the second illumination unit 25 in this embodiment is positioned above the object to be inspected 60 and closer to the roller 11 than the first illumination unit 23. Similar to the first illumination unit 23, the second illumination unit 25 is a line illumination composed of multiple LEDs arranged in parallel in a direction that is generally perpendicular and generally horizontal to the first transport direction D1. The second straight line 25a, which is parallel to the optical axis of the second illumination unit 25 and passes through the light emission surface 25e of the second illumination unit 25, extends in the vertical direction but is inclined downward toward the roller 12 and is not parallel to the first straight line 23a. This second straight line 25a passes between the imaging unit 30 and the roller 12 and does not intersect with the imaging unit 30. The second illumination unit 25 irradiates light L5 onto one surface 60S1 of the object to be inspected 60 being transported by the transport device 10, and this light L5 passes through the object to be inspected 60 from one surface 60S1 to the other surface 60S2. The portion of the object under inspection 60 through which light L5 from the second illumination unit 25 passes is in the shape of a line extending in a direction approximately perpendicular to the first transport direction D1, and overlaps with the portion of the object under inspection 60 through which light L3 from the first illumination unit 23 passes. The imaging range of the imaging unit 30 is located at or near the overlapping portion of the object under inspection 60 where light L3 from the first illumination unit 23 and light L5 from the second illumination unit 25 pass. In other words, the first illumination unit 23, the second illumination unit 25, and the imaging unit 30 are arranged so that the imaging range of the imaging unit 30 is located in this manner.

[0108] Furthermore, the lighting unit 21 refrains from emitting light L5 from the second lighting unit 25 when emitting light L3 from the first lighting unit 23, and refrains from emitting light L3 from the first lighting unit 23 when emitting light L5 from the second lighting unit 25. In other words, the timing at which the first lighting unit 23 irradiates one side 60S1 of the object under inspection 60 with light L3 is different from the timing at which the second lighting unit 25 irradiates one side 60S1 of the object under inspection 60 with light L5.

[0109] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0110] In this embodiment, similar to the fifth embodiment, the object to be inspected 60 is placed on the support film 13. The control unit CO controls the first illumination unit 23 to emit light L3. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the first illumination unit 23 irradiates light L3 onto one side 60S1 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10. At this time, light L5 from the second illumination unit 25 is not emitted. The control unit CO controls the imaging unit 30 to image the light L3 from the first illumination unit 23 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0111] In this embodiment, after the imaging unit 30 has completed the above imaging, the control unit CO controls the second illumination unit 25 to emit light L5. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, returning the object to be inspected 60 to the position where it was placed on the transport device 10. For this reason, the second illumination unit 25 irradiates light onto one side 60S1 of the object to be inspected 60 being transported in the second transport direction D2 by the transport device 10. At this time, light L3 from the first illumination unit 23 is not emitted. The control unit CO controls the imaging unit 30 to capture light L5 from the second illumination unit 25 that penetrates the object to be inspected 60 being transported in the second transport direction D2 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0112] As described above, in this embodiment, the first straight line 23a and the second straight line 25a are non-parallel to each other. Therefore, the illumination unit 21 can be understood to have a first illumination unit 23 that irradiates light L3 from a first direction onto one surface 60S1 of the object under inspection 60, and a second illumination unit 25 that irradiates light L5 from a second direction different from the first direction onto one surface 60S1 of the object under inspection 60. Furthermore, the imaging unit 30 can be understood to individually image the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 that are transmitted through the object under inspection 60.

[0113] In this embodiment, the inspection unit 40 determines the presence or absence of defects based on the image captured by the light L3 from the first illumination unit 23, and further determines the presence or absence of defects based on the image captured by the light L5 from the second illumination unit 25. Specifically, the inspection unit 40 determines the presence or absence of defects from the dark areas in the image captured by the light L3 from the first illumination unit 23. The first straight line 23a in this embodiment intersects with the imaging unit 30. Therefore, similar to the fifth embodiment, defects can be displayed as dark areas in the image of the light L3 from the first illumination unit 23 captured by the imaging unit 30. In this embodiment, similar to the fifth embodiment, the inspection unit 40 extracts areas in the image of the light L3 from the first illumination unit 23 captured by the imaging unit 30 where the brightness value is lower than a predetermined threshold, and calculates the area of ​​the extracted area. Then, if the calculated area is larger than the predetermined area, it outputs a signal to the control unit CO indicating the presence of a defect.

[0114] On the other hand, the second straight line 25a does not intersect with the imaging unit 30. Therefore, compared to the case where the second straight line 25a intersects with the imaging unit 30, of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25, light that passes through the object under inspection 60 from one side 60S1 to the other side 60S2 without incident on defects on one side 60S1 and the other side 60S2 of the object under inspection 60 is less likely to be incident on the imaging unit 30. In this embodiment, the position and orientation of the second illumination unit 25 relative to the imaging unit 30 are adjusted so that much of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that passes through the object under inspection 60 in this way does not occur on the imaging unit 30. On the other hand, of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that is incident on defects is absorbed or reflected by the defects. Therefore, the light that is reflected by the defects and also passes through the object under inspection 60 can occur on the imaging unit 30. Therefore, similar to the second embodiment, as shown in Figure 6, defects can be displayed as bright areas 71 surrounded by dark areas 72 in the image of light L5 from the second illumination unit 25 captured by the imaging unit 30. The inspection unit 40 of this embodiment, similar to the second embodiment, determines the presence or absence of defects based on the image captured of light L3 from the first illumination unit 23, and further determines the presence or absence of defects based on the image captured of light L5 from the second illumination unit 25, and outputs a signal corresponding to the determination to the control unit CO.

[0115] The control unit CO outputs a control signal to the display unit 50 corresponding to the signal input from the inspection unit 40, and displays the inspection result on the display unit 50. As described above, the object to be inspected 60 is returned to the position in which it was placed on the transport device 10. Therefore, similar to the fifth embodiment, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same.

[0116] As described above, in the inspection apparatus 1 of this embodiment, the illumination unit 21 has a first illumination unit 23 that irradiates light L3 from a first direction onto one surface 60S1 of the object to be inspected 60, and a second illumination unit 25 that irradiates light L5 from a second direction different from the first direction onto the same surface 60S1. The imaging unit 30 separately images the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 that are transmitted through the object to be inspected 60. The imaging unit 30 intersects with the first straight line 23a but not with the second straight line 25a. The inspection unit 40 determines the presence or absence of defects from the dark areas 72 in the image captured by the light L3 from the first illumination unit 23, and from the bright areas 71 in the image captured by the light L5 from the second illumination unit 25. Incidentally, because light propagates while diffusing, if the defect is thin and fibrous, such as a strand of hair or thread, such a defect tends not to be easily displayed as a dark area 72 in the image captured by the light L3 from the first illumination unit 23. However, in the inspection device 1 of this embodiment, such defects can be displayed as bright areas 71 in the image captured by the light L5 from the second illumination unit 25. Therefore, the inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign objects.

[0117] Furthermore, in the inspection apparatus 1 of this embodiment, the timing of when the first illumination unit 23 irradiates light L3 onto one surface 60S1 of the object to be inspected 60 and the timing of when the second illumination unit 25 irradiates light L5 onto the same surface 60S1 of the object to be inspected 60 are different. Therefore, the light L5 from the second illumination unit 25 does not appear in the image captured by the light L3 from the first illumination unit 23. Similarly, the light L3 from the first illumination unit 23 does not appear in the image captured by the light L5 from the second illumination unit 25. For this reason, the imaging unit 30 can capture the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 individually, even if it does not have, for example, a first imaging unit that captures the light L3 from the first illumination unit 23 and a second imaging unit that captures the light L5 from the second illumination unit 25.

[0118] Furthermore, from the viewpoint of increasing the detection accuracy of fine defects such as fibrous foreign matter, it is preferable that the light L5 from the second illumination unit 25 is collimated light or light focused on one surface 60S1 of the object under inspection 60. With this configuration, compared to the case where the light L5 from the second illumination unit 25 is diffuse light, the brightness of the bright area 71 when the defect is displayed as a bright area 71 can be increased, thereby increasing the detection accuracy of fine defects such as fibrous foreign matter.

[0119] (Seventh Embodiment) Next, a seventh embodiment, which is a second aspect of the present invention, will be described in detail with reference to Figure 12. Note that components identical or equivalent to those in the sixth embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0120] Figure 12 is a diagram showing the inspection apparatus in this embodiment in the same manner as in Figure 9. As shown in Figure 12, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the sixth embodiment in that the second illumination unit 25 is located downstream of the first illumination unit 23 in the first transport direction D1, and the imaging unit 30 has a first imaging unit 31 and a second imaging unit 32.

[0121] The second illumination unit 25 in this embodiment has the same configuration as the second illumination unit 25 in the sixth embodiment. However, as described above, the second illumination unit 25 is located downstream of the first illumination unit 23 in the first transport direction D1.

[0122] In this embodiment, the first imaging unit 31 has the same configuration as the imaging unit 30 of the sixth embodiment. Therefore, the first imaging unit 31 in this embodiment is a line sensor camera, located approximately directly below the first illumination unit 23, and intersects with the first straight line 23a. The first imaging unit 31 is positioned such that its imaging range extends in a direction approximately perpendicular to the first transport direction D1, and that the imaging range is located in or near a portion of the object under inspection 60 through which light L3 from the first illumination unit 23 passes. The first imaging unit 31 then images the light L3 from the first illumination unit 23 that passes through the object under inspection 60.

[0123] The second imaging unit 32 in this embodiment is a line sensor camera, similar to the first imaging unit 31. The second imaging unit 32 is located below the support film 13 between the rollers 11 and 12, in a direction parallel to the first transport direction D1, and is located closer to the rollers 12 than the first illumination unit 23 and the first imaging unit 31, and does not intersect with the first straight line 23a and the second straight line 25a. The second imaging unit 32 is positioned such that its imaging range extends in a direction generally perpendicular to the first transport direction D1, and that this imaging range is located in or near a portion of the object under inspection 60 through which light L5 from the second illumination unit 25 passes. The second imaging unit 32 then images the light L5 from the second illumination unit 25 that passes through the object under inspection 60.

[0124] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0125] In this embodiment, similar to the sixth embodiment, the object to be inspected 60 is placed on the support film 13. The control unit CO controls the first illumination unit 23 to emit light L3. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the first illumination unit 23 irradiates light L3 onto one side 60S1 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10. At this time, light L5 from the second illumination unit 25 is not emitted. The control unit CO controls the first imaging unit 31 to image the light L3 from the first illumination unit 23 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0126] Furthermore, similar to the sixth embodiment, the control unit CO controls the second illumination unit 25 to emit light L5 after the first imaging unit 31 has finished imaging. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, returning the object to be inspected 60 to the position where it was placed on the transport device 10. For this reason, the second illumination unit 25 irradiates light L5 onto one side 60S1 of the object to be inspected 60 being transported in the second transport direction D2 by the transport device 10. At this time, light L3 from the first illumination unit 23 is not emitted. The control unit CO controls the second imaging unit 32 to capture light L5 from the second illumination unit 25 that passes through the object to be inspected 60 being transported in the second transport direction D2 at predetermined time intervals, and outputs a two-dimensional image that includes the entire other surface 60S2 of the object to be inspected 60 to the inspection unit 40.

[0127] In other words, in this embodiment, the first imaging unit 31 captures the light L3 from the first illumination unit 23 that passes through the object to be inspected 60, and the second imaging unit 32 captures the light L5 from the second illumination unit 25 that passes through the object to be inspected 60.

[0128] In this embodiment, the first straight line 23a intersects with the first imaging unit 31. Therefore, similar to the sixth embodiment, defects in the object under inspection 60 may be displayed as dark areas in the image of light L3 from the first illumination unit 23 captured by the first imaging unit 31. Also, the second straight line 25a does not intersect with the second imaging unit 32. In this embodiment, similar to the sixth embodiment, the position and orientation of the second illumination unit 25 relative to the second imaging unit 32 are adjusted so that much of the light L5 irradiated onto the object under inspection 60 by the second illumination unit 25 that passes through the object under inspection 60 without entering defects in the object under inspection 60 does not enter the second imaging unit 32. Therefore, defects may be displayed as bright areas surrounded by dark areas in the image of light L5 from the second illumination unit 25 captured by the second imaging unit 32.

[0129] In this embodiment, the inspection unit 40, similar to the sixth embodiment, determines the presence or absence of defects from the dark areas in the image of light L3 from the first illumination unit 23 captured by the first imaging unit 31, and further determines the presence or absence of defects from the bright areas in the image of light L5 from the second illumination unit 25 captured by the second imaging unit 32.

[0130] Similar to the sixth embodiment, the control unit CO outputs a control signal corresponding to the signal input from the inspection unit 40 to the display unit 50, and displays the inspection result on the display unit 50. As described above, the object to be inspected 60 is returned to the position where it was placed on the transport device 10. Therefore, similar to the fifth embodiment, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same.

[0131] The inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign matter, in the same manner as in the sixth embodiment.

[0132] Furthermore, in the inspection apparatus 1 of this embodiment, the imaging unit 30 has a first imaging unit 31 that images light L3 from a first illumination unit 23 that passes through the object to be inspected 60, and a second imaging unit 32 that images light L5 from a second illumination unit 25 that passes through the object to be inspected 60. Therefore, with the inspection apparatus 1 of this embodiment, compared to the case where the imaging unit 30 does not have a second imaging unit 32, the degree of freedom of the position and orientation of the second illumination unit 25 relative to the object to be inspected 60 can be improved, and defects can be more easily displayed in the image captured by the light L5 from the second illumination unit 25 that passes through the object to be inspected 60. For this reason, the inspection apparatus 1 of this embodiment can further suppress a decrease in the detection accuracy of defects in the object to be inspected 60.

[0133] (Eighth embodiment) Next, an eighth embodiment, which is a second aspect of the present invention, will be described in detail with reference to Figure 13. Note that components identical or equivalent to those in the seventh embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0134] Figure 13 is a diagram showing the inspection apparatus in this embodiment in the same manner as in Figure 9. As shown in Figure 13, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the seventh embodiment in that the lighting unit 21 consists of a single lighting section, and the second imaging section 32 is tilted with respect to the vertical direction.

[0135] The lighting unit 21 of this embodiment has the same configuration as the lighting unit 21 of the fifth embodiment. Therefore, the lighting unit 21 of this embodiment is positioned above the object to be inspected 60 and is a line illumination consisting of multiple LEDs arranged in parallel in a direction that is generally perpendicular and generally horizontal to the first transport direction D1. Furthermore, the straight line 21a that is parallel to the optical axis of the lighting unit 21 and passes through the emission surface 21e of the lighting unit 21 is generally parallel to the vertical, the first imaging unit 31 intersects this straight line 21a, and the second imaging unit 32 does not intersect this straight line 21a. The portion of the object to be inspected 60 through which the light L1 from the lighting unit 21 is transmitted is a line extending in a direction that is generally perpendicular to the first transport direction D1. The imaging range of the first imaging unit 31 is located in the portion of the object to be inspected 60 through which the light L1 from the lighting unit 21 is transmitted, or in the vicinity of such portion.

[0136] As described above, the second imaging unit 32 of this embodiment is tilted with respect to the vertical direction. Specifically, the second imaging unit 32 is tilted with respect to the vertical direction such that the imaging range extends in a direction approximately perpendicular to the first transport direction D1 and that the imaging range is located in or near the area of ​​the object under inspection 60 through which light L1 from the illumination unit 21 passes. In other words, the second imaging unit 32 is positioned such that the imaging range is located in this manner.

[0137] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0138] In this embodiment, similar to the seventh embodiment, the object to be inspected 60 is placed on the support film 13. The control unit CO controls the illumination unit 21 to emit light L1. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the illumination unit 21 irradiates one side 60S1 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10 with light L1. The control unit CO controls the first imaging unit 31 and the second imaging unit 32 to capture the light L1 from the illumination unit 21 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0139] In other words, in this embodiment, the first imaging unit 31 intersecting the straight line 21a and the second imaging unit 32 not intersecting the straight line 21a each capture light L1 from the illumination unit 21 that passes through the object to be inspected 60.

[0140] In this embodiment, as described above, the first imaging unit 31 intersects with the straight line 21a, so, similar to the seventh embodiment, defects in the object under inspection 60 may be displayed as dark areas in the image of the light L1 from the illumination unit 21 captured by the first imaging unit 31. Also, the straight line 21a does not intersect with the second imaging unit 32. In this embodiment, similar to the seventh embodiment, the position and orientation of the second imaging unit 32 relative to the illumination unit 21 are adjusted so that much of the light L1 irradiated onto the object under inspection 60 by the illumination unit 21 that passes through the object under inspection 60 without entering defects in the object under inspection 60 does not enter the second imaging unit 32. For this reason, defects may be displayed as bright areas surrounded by dark areas in the image of the light L1 from the illumination unit 21 captured by the second imaging unit 32.

[0141] In this embodiment, the inspection unit 40, similar to the seventh embodiment, determines the presence or absence of defects from the dark areas in the image of the light L1 from the illumination unit 21 captured by the first imaging unit 31, and further determines the presence or absence of defects from the bright areas in the image of the light L1 from the illumination unit 21 captured by the second imaging unit 32.

[0142] Similar to the seventh embodiment, the control unit CO outputs a control signal to the display unit 50 corresponding to the signal input from the inspection unit 40, and displays the inspection result on the display unit 50. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, which is opposite to the first transport direction D1, and returns the object to be inspected 60 to the position in which it was placed on the transport device 10. As a result, the position of the object to be inspected 60 before inspection and the position of the object to be inspected 60 after inspection are approximately the same. Note that the control unit CO does not have to transport the object to be inspected 60 in the second transport direction D2 by the transport device 10.

[0143] The inspection device 1 of this embodiment can detect defects even if they are thin, such as fibrous foreign matter, in the same manner as in the seventh embodiment.

[0144] Furthermore, in the inspection apparatus 1 of this embodiment, the imaging unit 30 has a first imaging unit 31 that images light L3 from a first illumination unit 23 that passes through the object to be inspected 60, and a second imaging unit 32 that images light from a second illumination unit 25 that passes through the object to be inspected 60. Therefore, with the inspection apparatus 1 of this embodiment, compared to the case where the imaging unit 30 does not have a second imaging unit 32, the degree of freedom of the position and orientation of the second illumination unit 25 relative to the object to be inspected 60 can be improved, and defects can be more easily displayed in the image captured by the light L5 from the second illumination unit 25 that passes through the object to be inspected 60. For this reason, the inspection apparatus 1 of this embodiment can further suppress a decrease in the detection accuracy of defects in the object to be inspected 60.

[0145] (Ninth Embodiment) Next, a ninth embodiment, which is a second aspect of the present invention, will be described in detail with reference to Figure 14. Note that components identical or equivalent to those in the fifth embodiment are denoted by the same reference numerals unless otherwise specified, and redundant descriptions are omitted.

[0146] Figure 14 is a diagram showing the inspection apparatus in this embodiment in the same manner as in Figure 9. As shown in Figure 14, the inspection apparatus 1 of this embodiment differs from the inspection apparatus 1 of the fifth embodiment in that it includes a separate lighting unit 121 and a separate imaging unit 130.

[0147] Another lighting unit 121 in this embodiment has the same configuration as the lighting unit 21 in the first embodiment, and is positioned downstream of the lighting unit 21 and the imaging unit 30 in the first transport direction D1, and below the support film 13. The other lighting unit 121 irradiates the other surface 60S2 of the object to be inspected 60, which is transported by the transport device 10, with light L11 through the support film 13. In other words, the other lighting unit 121 is positioned on the other surface 60S2 side with respect to the object to be inspected 60, and irradiates this other surface 60S2 with light L11. Furthermore, the line 121a that is parallel to the optical axis of the other lighting unit 121 and passes through the light emission surface 121e of the other lighting unit 121 is generally parallel to the line 21a, but the line 121a and the line 21a may be non-parallel, and the line 121a and the line 21a may be non-parallel to the vertical direction. Furthermore, the distance between the lighting unit 21 and the other lighting unit 121 in a direction parallel to the first transport direction D1 is smaller than the width of the object under inspection 60 in a direction parallel to the first transport direction D1, but it may be larger than this width. Also, in the vertical direction perpendicular to the first transport direction D1, the emission surface 121e of the other lighting unit 121 is located on the support film 13 side of the imaging unit 30, but the positional relationship between the emission surface 121e and the imaging unit 30 is not particularly limited.

[0148] Another imaging unit 130 in this embodiment has the same configuration as the imaging unit 30 in the first embodiment, and is positioned downstream of the illumination unit 21 and the imaging unit 30 in the first transport direction D1, above the object under inspection 60, and captures light L11 from another illumination unit 121 that passes through the object under inspection 60. In other words, the other imaging unit 130 is positioned on one side 60S1 with respect to the object under inspection 60 and captures light L11 from another illumination unit 121 that passes through the object under inspection 60. In this embodiment, the other imaging unit 130 is a line sensor camera and is positioned approximately directly above the other illumination unit 121 and intersects with the line 121a. Also, in the vertical direction, the other imaging unit 130 is positioned on the opposite side from the support film 13 side from the emission surface 21e of the illumination unit 21, but the positional relationship between the other imaging unit 130 and the emission surface 21e is not particularly limited.

[0149] Next, the operation of the inspection device 1 of this embodiment for checking for defects in the object to be inspected 60 will be described.

[0150] In this embodiment, similar to the fifth embodiment, the object to be inspected 60 is placed on the support film 13. The control unit CO controls the illumination unit 21 to emit light L1. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the first transport direction D1. Therefore, the illumination unit 21 irradiates light L1 onto one side 60S1 of the object to be inspected 60 being transported in the first transport direction D1 by the transport device 10. At this time, light L11 from another illumination unit 121 is not emitted. The control unit CO controls the imaging unit 30 to image the light L1 from the illumination unit 21 that is passing through the object to be inspected 60 being transported in the first transport direction D1 at predetermined time intervals, and outputs a two-dimensional image including the entire other side 60S2 of the object to be inspected 60 to the inspection unit 40.

[0151] Furthermore, after the imaging unit 30 has finished taking the above images, the control unit CO controls another illumination unit 121 to emit light L11. The control unit CO also controls the transport device 10 to transport the object to be inspected 60 in the second transport direction D2, returning the object to be inspected 60 to the position where it was placed on the transport device 10. For this reason, the other illumination unit 121 irradiates light L11 onto one side 60S1 of the object to be inspected 60 as it is transported in the second transport direction D2 by the transport device 10. At this time, light L1 from the illumination unit 21 is not emitted. The control unit CO controls another imaging unit 130 to capture light L11 from another illumination unit 121 that passes through the object under inspection 60 being transported in the second transport direction D2 at predetermined time intervals, and outputs a two-dimensional image including the entire other surface 60S2 of the object under inspection 60 to the inspection unit 40.

[0152] In other words, in this embodiment, the imaging unit 30 captures the light L1 from the illumination unit 21 that passes through the object to be inspected 60, and another imaging unit 130 captures the light L11 from another illumination unit 121 that passes through the object to be inspected 60.

[0153] In this embodiment, the inspection unit 40, similar to the fifth embodiment, determines the presence or absence of defects from the bright areas in the image of light L1 from the illumination unit 21 captured by the imaging unit 30. The inspection unit 40 also determines the presence or absence of defects from the bright areas in the image of light L11 from another illumination unit 121 captured by another imaging unit 130.

[0154] Similar to the fifth embodiment, the control unit CO outputs a control signal corresponding to the signal input from the inspection unit 40 to the display unit 50, and displays the inspection result on the display unit 50.

[0155] In this embodiment, the presence or absence of defects is determined from an image of light L1 transmitted through the object under inspection 60 from one side 60S1 to the other side 60S2, and an image of light L11 transmitted through the object under inspection 60 from the other side 60S2 to the one side 60S1. Therefore, the accuracy of detecting defects on the surface of the object under inspection 60 can be improved compared to a system without a separate illumination unit 121 and a separate imaging unit 130.

[0156] Furthermore, the additional illumination unit 121 and the additional imaging unit 130 may be positioned upstream of the illumination unit 21 and the imaging unit 30 in the first transport direction D1. Also, imaging by the additional imaging unit 130 may be performed when the object under inspection 60 is being transported in the first transport direction D1. In this case, it is preferable that the additional imaging unit 130 is positioned away from the illumination unit 21 so that light L1 from the illumination unit 21 does not enter it. For example, it is preferable that the distance between the illumination unit 21 and the additional imaging unit 130 in a direction parallel to the first transport direction D1 is greater than the width of the object under inspection 60 in a direction parallel to the first transport direction D1. This allows imaging by the additional imaging unit 130 to be performed after imaging by the imaging unit 30 has been completed. Furthermore, when the object to be inspected 60 is transported in the first transport direction D1, the illumination unit 21 and another illumination unit 121 may alternately irradiate light L1 and L11 at predetermined time intervals, the imaging unit 30 may capture light L1 in synchronization with the illumination unit 21, and another imaging unit 130 may capture light L11 in synchronization with the other illumination unit 121. Also, any of the second to fourth embodiments can be applied to the other illumination unit 121 and the other imaging unit 130. For example, the other illumination unit 121 may have the same configuration as the illumination unit 21 of the second embodiment shown in Figure 5. Also, any of the sixth to eighth embodiments can be applied to the illumination unit 21 and the imaging unit 30. For example, the illumination unit 21 may have the same configuration as the illumination unit 21 of the sixth embodiment shown in Figure 11.

[0157] Although the first and second embodiments of the present invention have been described above with reference to the above embodiments, the present invention is not limited thereto.

[0158] For example, in the first to ninth embodiments, the object to be inspected 60 was described as an outer cover having ribs 61 along its entire outer circumference. However, the object to be inspected 60 only needs to include one translucent, convexly curved surface 60S1 and another concavely curved surface 60S2 facing this surface 60S1. For example, the ribs 61 may be provided on a part of the outer circumference of the object to be inspected 60, or the ribs 61 may not be provided on the outer circumference of the object to be inspected 60. Also, a part of the object to be inspected 60 may be colorless and transparent, while another part of the object to be inspected 60 is colored and transparent.

[0159] Furthermore, in the first to ninth embodiments, an illumination unit 21 that irradiates the object under inspection 60 with white light was described as an example. In the ninth embodiment, another illumination unit 121 that irradiates the object under inspection 60 with white light was described as an example. However, the color of the light irradiated onto the object under inspection 60 by the illumination unit 21 or the other illumination unit 121 is not particularly limited. If a part of the object under inspection 60 is colorless and transparent, and another part of the object under inspection 60 is colored and transparent, it is preferable that the color of the light irradiated onto the object under inspection 60 by the illumination unit 21 or the other illumination unit 121 is approximately the same color as the colored and transparent part of the object under inspection 60. By using such a configuration, unevenness in image brightness due to color differences can be suppressed, and a decrease in the accuracy of detecting defects in the object under inspection 60 can be suppressed.

[0160] Furthermore, in the second, third, sixth, and seventh embodiments, an inspection unit 40 was described as an example in which the presence or absence of defects is determined from the dark areas in the image captured by the light L3 from the first illumination unit 23, and the presence or absence of defects is determined from the bright areas in the image captured by the light L5 from the second illumination unit 25. However, in the case where the illumination unit 21 has a first illumination unit 23 that irradiates the other surface 60S2 of the object to be inspected 60 from a first direction and a second illumination unit 25 that irradiates the other surface 60S2 from a second direction different from the first direction, and the imaging unit 30 individually images the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 that penetrate the object to be inspected 60, the inspection unit 40 only needs to determine the presence or absence of defects based on the image captured by the imaging unit 30. In such an inspection device, since the first and second directions are different, the absorption, reflection, and refraction of light caused by defects in the object under inspection 60 when light is irradiated from the first direction are different from when light is irradiated from the second direction. As a result, defects that were difficult to display in the image when light is irradiated from the first direction may be easily displayed in the image when light is irradiated from the second direction, and defects that were difficult to display in the image when light is irradiated from the second direction may be easily displayed in the image when light is irradiated from the second direction. Therefore, such an inspection device can suppress a decrease in the detection accuracy of defects in the object under inspection 60 compared to the case where the illumination unit 21 does not have a second illumination unit 25.

[0161] Furthermore, in the second and sixth embodiments, an imaging unit 30 was described as an example in which the imaging unit 30 is parallel to the optical axis of the second illumination unit 25 and does not intersect with the second straight line 25a that passes through the light emission surface 25e of the second illumination unit 25. However, in the second and sixth embodiments, if the first straight line 23a and the second straight line 25a are not parallel, the imaging unit 30 may intersect with the second straight line 25a. In this case, for example, the inspection unit 40 determines the presence or absence of defects from the dark areas in the image captured by the light L5 from the second illumination unit 25, similar to how the presence or absence of defects is determined based on the image captured by the light L3 from the first illumination unit 23. Even with this configuration, because the first straight line 23a and the second straight line 25a are non-parallel, defects that were difficult to display in the image captured by light L3 from the first illumination unit 23 may be easily displayed in the image captured by light L5 from the second illumination unit 25, and vice versa. Therefore, defects that were difficult to display in the image captured by light L5 from the second illumination unit 25 may be easily displayed in the image captured by light L3 from the first illumination unit 23. For this reason, such an inspection device can suppress a decrease in the accuracy of detecting defects in the object under inspection 60 compared to the case where the illumination unit 21 does not have the second illumination unit 25.

[0162] Furthermore, in the second and sixth embodiments, the second lighting unit 25, located upstream of the first conveying direction D1 from the first lighting unit 23, was described as an example. However, in the second and sixth embodiments, the position of the second lighting unit 25 relative to the first lighting unit 23 is not particularly limited, and the second lighting unit 25 may be located downstream of the first lighting unit 23 from the first conveying direction D1. In this case, for example, in the second embodiment, the second lighting unit 25 is positioned such that the second straight line 25a is inclined upward in the direction opposite to the first conveying direction D1, and in the sixth embodiment, the second lighting unit 25 is positioned such that the second straight line 25a is inclined downward in the direction opposite to the first conveying direction D1. Note that the first straight line 23a may not be parallel to the vertical direction.

[0163] Furthermore, in the second and sixth embodiments, when the object to be inspected 60 is transported in the first transport direction D1, the first illumination unit 23 and the second illumination unit 25 may alternately emit light L3 and L5 at predetermined time intervals, and the imaging unit 30 may alternately image the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 in synchronization with the irradiation of light L3 and L5 from the first illumination unit 23 and the second illumination unit 25. Even with such a configuration, the imaging unit 30 can individually image the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25. Also, the object to be inspected 60 is transported in only one direction. Therefore, the configuration of the transport device can be simplified compared to the case where the object to be inspected 60 is transported in multiple directions. In addition, the time required for the inspection of defects in the object to be inspected 60 by the inspection device 1 can be shortened.

[0164] Furthermore, in the third and seventh embodiments, a second imaging unit 32 was described as capturing light L5 from a second illumination unit 25 that passes through the object to be inspected 60 when the object to be inspected 60 is being transported in a second transport direction D2. However, in the third and seventh embodiments, the second imaging unit 32 may capture light L5 from a second illumination unit 25 that passes through the object to be inspected 60 when the object to be inspected 60 is being transported in a first transport direction D1. In this case, for example, the first illumination unit 23 and the second illumination unit 25 are separated, and the first imaging unit 31 and the second imaging unit 32 are separated, so that light L3 from the first illumination unit 23 is less likely to enter the second imaging unit 32, and light L5 from the second illumination unit 25 is less likely to enter the first imaging unit 31. In this way, even if the illumination unit 21 emits light L3 and L5 simultaneously from the first illumination unit 23 and the second illumination unit 25, the imaging unit 30 can individually image the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25. Furthermore, the object under inspection 60 is transported in only one direction. Therefore, the configuration of the transport device can be simplified compared to the case where the object under inspection 60 is transported in multiple directions. In addition, the time required for the inspection device 1 to inspect the object under inspection 60 for defects can be shortened.

[0165] Furthermore, in the third and seventh embodiments, the second imaging unit 32 was described as being parallel to the optical axis of the second illumination unit 25 and not intersecting the second straight line 25a that passes through the light emission surface 25e of the second illumination unit 25. However, in the third embodiment, if the first straight line 23a and the second straight line 25a are not parallel, the second imaging unit 32 may intersect the second straight line 25a. In this case, for example, the inspection unit 40 determines the presence or absence of defects from the dark areas in the image captured by the second imaging unit 32 using light L5 from the second illumination unit 25, similar to how the first imaging unit 31 determines the presence or absence of defects based on the image captured using light L3 from the first illumination unit 23. Even with this configuration, because the first straight line 23a and the second straight line 25a are non-parallel, defects that were difficult to display in the image captured by light L3 from the first illumination unit 23 may be easily displayed in the image captured by light L5 from the second illumination unit 25, and vice versa. Therefore, defects that were difficult to display in the image captured by light L5 from the second illumination unit 25 may be easily displayed in the image captured by light L3 from the first illumination unit 23. For this reason, such an inspection device can suppress a decrease in the accuracy of detecting defects in the object under inspection 60 compared to the case where the illumination unit 21 does not have the second illumination unit 25.

[0166] Furthermore, in the third and seventh embodiments, a second illumination unit 25 located downstream of the first illumination unit 23 in the first transport direction D1, and a second imaging unit 32 located downstream of the first imaging unit 31 in the first transport direction D1 were described as examples. However, in the third and seventh embodiments, the positions of the first illumination unit 23, the second illumination unit 25, the first imaging unit 31, and the second imaging unit 32 in the direction parallel to the first transport direction D1 are not particularly limited. For example, the second illumination unit 25 may be located upstream of the first illumination unit 23 in the first transport direction D1. Alternatively, the second illumination unit 25 may be located upstream of the first illumination unit 23 in the first transport direction D1, and the second imaging unit 32 may be located upstream of the first imaging unit 31 in the first transport direction D1. In addition, in the third embodiment, the second illumination unit 25 may be arranged such that the second straight line 25a is inclined upward in the direction opposite to the first transport direction D1. Furthermore, in the seventh embodiment, the second illumination unit 25 may be arranged such that the second straight line 25a is inclined downward in the direction opposite to the first transport direction D1. In terms of suppressing the incidence of light L5 from the second illumination unit 25 onto the first imaging unit 31, as in the third and seventh embodiments, it is preferable that the second straight line 25a is inclined toward the side where the imaging unit 30 is located, away from the second illumination unit 25, on the opposite side from the first imaging unit 31 side with respect to the second illumination unit 25 in a direction parallel to the first transport direction D1. Also, in terms of miniaturization, it is preferable to arrange the second illumination unit 25 such that the second straight line 25a passes between the first illumination unit 23 and the first imaging unit 31.

[0167] Furthermore, in the second, third, sixth, and seventh embodiments, the inspection device 1 was described as one in which the light L3 from the first illumination unit 23 is imaged first, and then the light L5 from the second illumination unit 25 is imaged. However, in the third embodiment, the inspection device 1 may image the light L5 from the second illumination unit 25 first, and then the light L3 from the first illumination unit 23.

[0168] Furthermore, in the third and seventh embodiments, when the object to be inspected 60 is transported in the first transport direction D1, the first illumination unit 23 and the second illumination unit 25 may alternately emit light L3 and L5 at predetermined time intervals, the first imaging unit 31 may capture the light L3 from the first illumination unit 23 in synchronization with the irradiation of light L3 from the first illumination unit 23, and the second imaging unit 32 may capture the light L5 from the second illumination unit 25 in synchronization with the irradiation of light L5 from the second illumination unit 25. Even with such a configuration, the imaging unit 30 can capture the light L3 from the first illumination unit 23 and the light L5 from the second illumination unit 25 individually. Also, the object to be inspected 60 is transported in only one direction. For this reason, the configuration of the transport device can be simplified compared to the case where the object to be inspected 60 is transported in multiple directions. In addition, the time required for the inspection of defects in the object to be inspected 60 by the inspection device 1 can be shortened.

[0169] Furthermore, in the first, fourth, fifth, eighth, and ninth embodiments, a lighting unit 21 that is a single line of illumination was described as an example, and in the second, third, sixth, and seventh embodiments, a lighting unit 21 having a first illumination section 23 and a second illumination section 25 that are line of illumination was described as an example. Furthermore, in the ninth embodiment, another lighting unit 121 that is a single line of illumination was described as an example. However, the lighting unit 21 and the other lighting unit 121 are not particularly limited. For example, the lighting unit 21 in the first, fourth, fifth, eighth, and ninth embodiments and the other lighting unit 121 in the ninth embodiment may be planar illumination with LEDs arranged in two dimensions. Also, the first illumination section 23 and the second illumination section 25 in the second, third, sixth, and seventh embodiments may be planar illumination with LEDs arranged in two dimensions.

[0170] Furthermore, in the first, second, fifth, sixth, and ninth embodiments, an imaging unit 30 which is a single line sensor camera was described as an example, and in the third, fourth, seventh, and eighth embodiments, an imaging unit 30 having a first imaging unit 31 and a second imaging unit 32 which are line sensor cameras was described as an example. In the ninth embodiment, another imaging unit 130 which is a single line sensor camera was described as an example. However, the imaging unit 30 and the other imaging unit 130 are not particularly limited. For example, the imaging unit 30 in the first, second, fifth, sixth, and ninth embodiments and the other imaging unit 130 in the ninth embodiment may be area sensor cameras. Also, the first imaging unit 31 and the second imaging unit 32 in the third, fourth, seventh, and eighth embodiments may be area sensor cameras.

[0171] Furthermore, in the above embodiment, a transport device 10 that moves the object to be inspected 60 relative to the lighting unit 21 and the imaging unit 30 was described as an example. However, the transport device may also move the lighting unit 21 and the imaging unit 30 relative to the object to be inspected 60.

[0172] According to a first aspect of the present invention, an inspection device is provided that can suppress a decrease in the detection accuracy of surface defects of an object under inspection, and according to a second aspect of the present invention, an inspection device is provided that can suppress a narrowing of the inspection range for surface defects of an object under inspection, and can be used in fields such as inspection devices for the surface of lighting fixtures.

Claims

1. A lighting unit comprising one convexly curved surface and another concavely curved surface facing the first surface, having light-transmitting properties, and positioned on the other surface side with respect to the object to be inspected used in a lighting fixture, to irradiate the other surface with light; An imaging unit positioned on one side of the object to be inspected with respect to the object to be inspected, and imaging the light from the illumination unit that passes through the object to be inspected, An inspection unit that determines whether or not there are defects on one surface and the other surface of the object to be inspected based on the image captured by the imaging unit, A transparent support film that crosses between the lighting unit and the imaging unit to transport the object to be inspected, Equipped with An inspection device characterized by the following features.

2. The imaging unit includes a first imaging unit that images light from the lighting unit that is parallel to the optical axis of the lighting unit, intersects with a straight line passing through the light emission surface of the lighting unit, and transmits light through the object to be inspected, and a second imaging unit that images light from the lighting unit that does not intersect with the straight line and transmits light through the object to be inspected. The inspection unit determines the presence or absence of the defect from the dark areas in the image captured by the first imaging unit, and also determines the presence or absence of the defect from the bright areas in the image captured by the second imaging unit. The inspection apparatus according to feature 1.

3. A lighting unit comprising one convexly curved surface and another concavely curved surface facing the aforementioned surface, having light-transmitting properties, and positioned on the side of the one surface relative to the object to be inspected used in a lighting fixture, to irradiate the one surface with light; An imaging unit positioned on the other side of the object to be inspected with respect to the object to be inspected, and imaging the light from the illumination unit that passes through the object to be inspected, An inspection unit that determines whether or not there are defects on one surface and the other surface of the object to be inspected based on the image captured by the imaging unit, A transparent support film that crosses between the lighting unit and the imaging unit to transport the object to be inspected, Equipped with An inspection device characterized by the following features.

4. The imaging unit includes a first imaging unit that images light from the lighting unit that is parallel to the optical axis of the lighting unit, intersects with a straight line passing through the light emission surface of the lighting unit, and transmits light through the object to be inspected, and a second imaging unit that images light from the lighting unit that does not intersect with the straight line and transmits light through the object to be inspected. The inspection unit determines the presence or absence of the defect from the dark areas in the image captured by the first imaging unit, and also determines the presence or absence of the defect from the bright areas in the image captured by the second imaging unit. The inspection apparatus according to feature 3.

5. A separate lighting unit is positioned on the other side of the object to be inspected, with respect to the object to be inspected, and irradiates light onto the other side. A separate imaging unit is positioned on one side of the object to be inspected with respect to the object to be inspected and captures light from another illumination unit that passes through the object to be inspected, Furthermore, The inspection unit determines whether or not the defect exists based on the image captured by the imaging unit and the image captured by the other imaging unit. The imaging unit intersects a first straight line that is parallel to the optical axis of the illumination unit and passes through the light emission surface of the illumination unit. The aforementioned imaging unit intersects with a second straight line that is parallel to the optical axis of the aforementioned illumination unit and passes through the light emission surface of the aforementioned illumination unit. The first line and the second line do not intersect between the illumination unit and the imaging unit. The inspection apparatus according to claim 3 or 4.

6. The outer edge of the object to be inspected is provided with light-transmitting ribs that protrude toward the other side. The object to be inspected is placed on the support film with the end of the rib in contact with the support film. The other surface and the one surface are separated from the support film. The inspection apparatus according to any one of claims 1 to 5.

Images