JP2019211325A - Defect inspection device - Google Patents

Abstract

To provide a defect inspection device that can highly accurately detect defects with an amount of light of inspection light reaching an inspected object much increased in comparison to a conventional device.SOLUTION: A defect inspection device 10 comprises: a light projection device 16; and a light reception device 11, and between an inspected object 15 and the light projection device 11, provided is an inspection light shield system 20 in order for the inspection light not to reach the light reception device 11 as a bright field of view. In the inspection light shield system 20, provided are: an inspected object side shield plate 21 having a first shield part 21a juxtaposed; and a light projection device side shield plate 22 having a second shield part 22a juxtaposed, and a length of one part of the first shield plate 21a in a prescribed direction or one part of the second shield part 22a therein is shorter than that of the light projection device 16. Due to this configuration, the inspection light reaching the inspected object 15 is not blocked more than necessary, and an amount of light of scattering light generating by defects of the inspected object 15 much increases, which in turn the defect can be highly accurately detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a defect inspection apparatus. More particularly, the present invention relates to a defect inspection apparatus that inspects an object to be inspected by an optical method.

  In an object to be inspected which can be a flat surface such as a film, an inspection using an optical method is performed for inspecting a defect on the surface, for example, a streak-like scratch. Among inspections using this optical method, inspection light emitted from the light source is not directly transmitted to the light receiving device, and only light scattered by the inspection light at the defect is allowed to reach the light receiving device. A technique, that is, an inspection technique using a dark field is known. Patent Document 1 discloses a dark field type defect detection apparatus.

  Patent Document 2 discloses a defect detection apparatus in which a function of an inspection method using a dark field is added to a bright-field type defect detection apparatus. That is, in the defect inspection apparatus of Patent Document 2, the inspection light from one light emitting means is allowed to reach the detection means directly (bright field type), and the inspection light from the other light emitting means is allowed to reach the detection means indirectly. (Dark field type). In FIG. 6 of this patent document 2, in order to obtain the function of the inspection method using a dark field, two light shielding portions are provided on the top and bottom, and each light shielding portion includes a plurality of shielding members. It is configured.

JP 2004-309287 A JP 2006-98198 A

  FIG. 10 shows a side view of a conventional dark field type defect inspection apparatus 50. In the present specification, a defect inspection apparatus 50 when the inspection target 55 is transparent is described. In FIG. 10, the direction from the light projecting device 56 toward the light receiving device 51, that is, the vertical direction on the paper surface of FIG. 10 is the Z direction, the traveling direction of the inspection target 55, that is, the horizontal direction on the paper surface of FIG. The depth direction on the paper surface of FIG. The defect inspection apparatus 50 is provided with a light projecting device 56 and a light receiving device 51. The inspection light emitted from the light projecting device 56 should pass through the transparent inspection target 55 and reach the light receiving device 51. However, since there is the inspection light shielding system 58, the inspection light is received as a bright field by the light receiving device. The inspection light scattered by the defect does not reach 51, but reaches the light receiving device 51. Conventionally, in the traveling direction of the inspection target 55, that is, the Y direction, the lengths of the first shielding part 59 and the second shielding part 60 constituting the inspection light shielding system 58 are the width of the inspection light irradiated by the light projecting device 56. It was longer than (the length in the Y direction). This is to more reliably prevent the inspection light from the light projecting device 56 from reaching the light receiving device 51 as a bright field.

  However, since the lengths of the first shielding portion 59 and the second shielding portion 60 of the conventional defect inspection apparatus 50 are long, the amount of inspection light reaching the inspection target 55 is excessively limited. There is a problem that the amount of inspection light irradiated to the defect 55 is too small.

  In view of the above circumstances, an object of the present invention is to provide a defect inspection apparatus capable of detecting a defect with high accuracy by increasing the amount of inspection light reaching an object to be inspected more than ever.

A defect inspection apparatus according to a first aspect of the present invention is an apparatus for inspecting a defect of an inspection target having a flat surface, a line light source projector that emits inspection light toward the inspection target, and the projection And the light receiving device that receives the inspection light from the optical device via the inspection target, and the inspection light is a bright field between the inspection target and the light projecting device. An inspection light shielding system for preventing the light from reaching the light receiving device is provided. In the inspection light shielding system, the first shielding portions are arranged in a linear direction of the inspection light, so that the linear inspection light of the inspection light is arranged. Light projection capable of intermittently shielding a part of the linear inspection light by arranging a second shielding part in the linear direction of the inspection light and the inspection target side shielding plate capable of intermittently shielding a part. A device-side shielding plate, and is provided by the light projecting device and the light receiving device. A length of a part of the first shielding part or a part of the second shielding part in a direction perpendicular to the linear direction of the inspection light in a plane perpendicular to the surface to be formed is the light projecting device. It is characterized by being shorter than the length in the direction perpendicular to the linear direction.
The defect inspection apparatus according to a second aspect of the present invention is the defect inspection apparatus according to the first aspect, wherein all of the first shielding portion and all of the second shielding portion are surfaces perpendicular to a surface formed by the light projecting device and the light receiving device. A parallelogram shape, the parallelogram having two sides parallel to the linear direction of the inspection light and two parallel sides not perpendicular to the linear direction of the inspection light It is characterized by being formed from.
The defect inspection apparatus according to a third aspect of the present invention is characterized in that, in the first or second aspect, an auxiliary shielding plate is provided between the inspected object side shielding plate and the inspected object.
The defect inspection apparatus according to a fourth aspect of the present invention is the defect inspection apparatus according to any one of the first to third aspects, wherein the shortest length of the second shielding portion in the direction perpendicular to the linear direction of the inspection light is the first length. It is characterized by being longer than the longest length in the direction perpendicular to the linear direction of the inspection light of one shielding part.

According to the first aspect of the invention, the defect inspection apparatus includes the inspection light shielding system for preventing the inspection light from reaching the light receiving device as a bright field, and this direction is perpendicular to the linear direction of the inspection light. Since the lengths of the first shielding portion and the second shielding portion constituting the inspection light shielding system are shorter than the width of the inspection light, the inspection light reaching the object to be inspected is not blocked more than necessary, The amount of scattered light generated by the defect to be inspected is increased, and the defect can be detected with high accuracy.
According to the second aspect of the invention, the shielding portion has two parallel sides that are not perpendicular to the linear direction of the inspection light, so that the shielding portion has an end surface perpendicular to the linear direction of the inspection light. In addition, since the inspection light is reflected by such an end face, it is possible to suppress the generated disturbance light from reaching the sensor unit, and to detect a defect with higher accuracy.
According to the third invention, since the auxiliary shielding plate is provided between the inspected object side shielding plate and the inspected object, the amount of the inspection light can be prevented from becoming too large, and the image level is expected. It is possible to prevent the defect contrast from decreasing without increasing.
According to the fourth invention, in the direction perpendicular to the linear direction of the inspection light, the length of the second shielding portion close to the light projecting device is longer than the length of the first shielding portion close to the inspection target, Unnecessary light entering the lens constituting the light receiving device is reduced, and deterioration in inspection accuracy due to irregular reflection inside the lens can be suppressed.

It is explanatory drawing of the inspection light shielding system which comprises the defect inspection apparatus which concerns on 1st Embodiment of this invention. It is a front view of the defect inspection apparatus which concerns on 1st Embodiment of this invention. It is a side view of the defect inspection apparatus of FIG. It is explanatory drawing of the inspection light shielding system which comprises the defect inspection apparatus which concerns on 2nd Embodiment of this invention. It is a side view of the defect inspection apparatus which concerns on 3rd Embodiment of this invention. It is a side view of the defect inspection apparatus which concerns on 4th Embodiment of this invention. It is explanatory drawing of the inspection light shielding system which comprises the defect inspection apparatus which concerns on 5th Embodiment of this invention. It is the 1st explanatory view of a dark field type inspection method. It is the 2nd explanatory view of a dark field type inspection method. It is a side view of the conventional defect inspection apparatus.

  Next, an embodiment of the present invention will be described with reference to the drawings. However, the embodiment shown below exemplifies the defect inspection apparatus 10 for embodying the technical idea of the present invention, and the present invention does not specify the defect inspection apparatus 10 as follows. Note that the size or positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation.

(First embodiment)
FIG. 2 is a schematic front view of the defect inspection apparatus 10 according to the first embodiment of the present invention, and FIG. 3 is a schematic side view of the defect inspection apparatus 10. In the present embodiment, the direction from the light projecting device 16 toward the light receiving device 11, that is, the vertical direction on the paper surface of FIGS. 2 and 3 is the Z direction, and the linear direction of the inspection light, that is, the horizontal direction on the paper surface of FIG. The traveling direction of the inspection object 15 that is perpendicular to the X direction and the linear direction of the inspection light, that is, the left-right direction on the paper surface of FIG. In each drawing, a broken line K indicates the outermost end of the inspection light from the light projecting device 16 toward the light receiving device 11. The defect inspection apparatus 10 according to the present invention is an apparatus that inspects a defect of an inspection target 15 whose surface can be a flat surface such as a resin film by an optical technique. The defect inspection apparatus 10 according to the present invention is a main object to be inspected 15 that can transmit light and can have a flat surface by applying tension, like a transparent resin film. In addition, a metal having a flat surface and capable of reflecting light, a thick extruded resin product, paper, glass, or the like can also be used as the inspection object 15. In the claims, the expression “via the object to be inspected” is used as a superordinate concept including the meanings of “through the object to be inspected” or “reflected by the object to be inspected”. ing.

  The defect inspection apparatus 10 according to the present embodiment includes a line light source projection device 16 that emits inspection light toward the inspection target 15 and the inspection light from the light projection device 16 via the inspection target 15. And a light receiving device 11 for receiving light. The inspection object 15 is sequentially sent from right to left on the paper surface of FIG. 3 by two rolls (not shown) provided before and after the defect inspection apparatus 10, and the defects of the inspection object 15 are continuously detected. Existence is checked. The “inspected object 15 whose surface is a flat surface” described in the claims means that the surface of the inspected object 15 being inspected can form a flat surface. .

  The light receiving device 11 has a known configuration and includes a sensor unit 12 and a lens 13. In the sensor unit 12, a plurality of light receiving elements 12 a are arranged in a straight line in the direction perpendicular to the traveling direction of the inspection target 15, that is, in the X direction (depth direction in FIG. 3). At least two or more light receiving elements 12a are arranged in the X direction. The light receiving element 12a can convert the intensity of the received light into an electric signal. Also, a plurality of light receiving elements 12a may be arranged in the Y direction.

  In addition, the description of “vertical” or “parallel” in this specification does not have to be strictly vertical or parallel, and the portion in which the term is used can sufficiently satisfy the function of the portion. It is meant to include a range that is vertical or parallel, ie, “substantially vertical” or “substantially parallel”.

  The light projecting device 16 has a known configuration and has a light source 17 therein. The light source 17 is an LED having a linear shape extending in the X direction. The light projecting device 16 is provided with a case 18 opened in only one direction. The inspection light emitted from the light source 17 passes through the opening and travels toward the light receiving device 11. In the present embodiment, “the length of the light projecting device 16 in the direction perpendicular to the linear direction” described in the claims is Y in the inspection light opening 18a of the case 18 as shown in FIG. It becomes the length of the direction. Further, the light source 17 has a light-scattering resin, a glass plate, or a paper such as Japanese paper having a rough surface or containing an additive in order to soften the irradiated light. Therefore, it is preferable that the entire case 18 is covered or the inspection light opening 18a of the case 18 is covered.

  The defect inspection apparatus 10 according to the present embodiment performs an inspection to prevent the inspection light emitted by the light projecting device 16 from reaching the light receiving device 11 as a bright field between the inspection target 15 and the light projecting device 16. A light shielding system 20 is provided. The inspection light shielding system 20 includes an inspection target side shielding plate 21 and a light projecting device side shielding plate 22. In the present specification, the description of “shielding plate” may mean a combination of the inspection target side shielding plate 21 and the light projecting device side shielding plate 22. The inspection target side shielding plate 21 can intermittently shield a part of the linear inspection light by arranging the first shielding portions 21a in the linear direction of the inspection light, that is, the X direction. Similarly, the light projecting device side shielding plate 22 can also intermittently shield a part of the linear inspection light by arranging the second shielding portions 22a in the X direction. 2 and 3, in order to make it easy to understand the existence of the first shielding part 21a and the second shielding part 22a, the inspected object-side shielding plate 21 and the light projecting device-side shielding plate 22 are provided with the first shielding part 21a. Parts other than the second shielding part 22a are not described. In the present specification, the description of “shielding part” may mean a combination of the first shielding part 21a and the second shielding part 22a. In the present embodiment, the inspection light reaches the light receiving device 11 only as a dark field in both the X direction and the Y direction. However, “the inspection light reaches the light receiving device as a bright field” in the claims. The description “to avoid” includes the case where only the inspection light in the X direction or the Y direction reaches the light receiving device 11 as a dark field.

  Here, the configuration and operation of the inspection light shielding system 20 of the defect inspection apparatus 10 according to the present embodiment will be described with reference to FIGS. FIG. 8 is a first explanatory diagram of a dark field type inspection method, and shows one example of a dark field type inspection method. FIG. 8 is an enlarged view of the inspection light shielding system 20 of FIG. 2 when the defect inspection apparatus 10 is viewed from the front. FIG. 9 is a second explanatory diagram of the dark field type inspection method, and shows the action of the dark field type inspection method. FIG. 9A schematically shows FIG. 3 in which the defect inspection apparatus 10 is viewed from the side, and FIGS. 9B and 9C are SS arrows in FIG. 9A. FIG. In FIG. 9B and FIG. 9C, the shape of the defect D is different.

  A dark field inspection method will be described with reference to FIG. In the dark field inspection method, the focal position F of the light receiving device 11 is the surface of the inspection target 15. The light receiving device 11 is a device that receives the second light beam W emitted from the focal position F. The light projecting device 16 is a device that irradiates the first light beam V toward the focal position F. In the dark field inspection method, all the second light rays W incident on the light receiving device 11 do not coincide with the direction of the first light rays V emitted from the light projecting device 16 toward the focal position F, and the first light rays Only the second light beam W generated by scattering V at the focal position F is received by the light receiving device 11.

  In order to realize the above dark field type inspection method, in the defect inspection apparatus 10 of the present embodiment, as shown in FIG. 8, the X-direction positions of the first shielding portion 21a and the second shielding portion 22a are shifted. The first light beam V is irradiated toward the inspection target 15 at a predetermined angle toward the inspection target 15 where the focal position F is present. In this predetermined angle, in FIG. 8, the angle δ1 between the first light ray V1 which is a part of the first light ray V and the light source 17 becomes the maximum value, and the first light ray V2 which is a part of the first light ray V The angle δ2 due to the light source 17 is the minimum value. The direction of the first light ray V existing between these two angles δ1 and δ2 and the direction of all the second light rays W incident on the light receiving device 11 from the focal position F do not coincide with each other. The position in the X direction is shifted from the position in the X direction of the second shielding portion 22a.

  FIG. 1 is an explanatory diagram of an inspection light shielding system 20 constituting the defect inspection apparatus 10 according to the present embodiment. As described above, the inspection light shielding system 20 is configured to include the two shielding plates (FIGS. (A) and (B)) shown on the left side in FIG. In the upper left figure (A), the inspected object side shielding plate 21 is described, and in the lower left figure (B), the light projecting device side shielding plate 22 is described. In the right figure (C), a part of the inspection light shielding system 20 has the inspected object side shielding plate 21 on the upper side (front side in FIG. 1), and the light projecting device side shielding plate 22 on the lower side. It is described in a state of being (the back side in FIG. 1). 1 shows a surface perpendicular to the surface formed by the linear light source 17 constituting the light projecting device 16 and the sensor unit 12 constituting the light receiving device 11 described in the claims. It represents the state. Specifically, it is a diagram when the lower side of the shielding target side shielding plate 21 is viewed from the upper side on the paper surface of FIG.

The shielding plate is manufactured by performing removal processing such as laser processing or punching processing from a non-transparent plate-shaped member, or performing molding using a mold and 3D printing. The material of the shielding plate is plastic, metal, etc., but the material is selected in consideration of workability, durability, and light shielding properties. The inspected object-side shielding plate 21 according to the present embodiment is provided with long left and right spaces in the center of the top and bottom and the left and right in the paper surface of FIG. 1, and a rectangular first shielding portion 21a is intermittently formed in this space portion. It is arranged to line up. The first shielding part 21a is fixed by a support piece 23 to the edge part of the inspected object-side shielding plate 21 provided vertically on the paper surface of FIG. Thus, by arrange | positioning so that the 1st shielding part 21a may be located in a line, a part of linear test | inspection light along the longitudinal direction of the to-be-tested object side shielding board 21 is interrupted | blocked intermittently. Further, the width of the support piece 23 in the X direction is made narrower than the width of the shielding plate in the X direction, and the shielding of the inspection light at the portion where the support piece 23 is present is suppressed.
Note that the shielding plate can be fixed to the light projecting device 16 by providing a dedicated support member or by integrating the light shielding device 16 with the light projecting device 16.

  The first shielding part 21a located on the inspection object 15 side has a distance from the inspection object 15 of preferably 20 mm or more and 300 mm or less, and more preferably 50 mm or more and 100 mm or less.

  Further, the light projecting device side shielding plate 22 according to the present embodiment is arranged so that the rectangular second shielding portions 22a are intermittently arranged in the same manner as the inspection target side shielding plate 21. The 2nd shielding part 22a is being fixed to the edge part provided up and down in the paper surface of FIG. Thus, by arrange | positioning so that the 2nd shielding part 22a may be located in a line, a part of linear test | inspection light along the longitudinal direction of the light projection apparatus side shielding board 22 is interrupted | blocked intermittently.

  The difference between the inspected object side shielding plate 21 and the light projecting apparatus side shielding plate 22 is that the position of the first shielding part 21a with respect to the entire inspected object side shielding plate 21 and the first with respect to the entire light projecting apparatus side shielding plate 22 are the same. 2 is the position of the shield 22a. Due to the difference in position, the inspection light from the light projecting device 16 does not reach the light receiving device 11 as a bright field.

  As shown in FIG. 1, in the defect inspection apparatus 10 of the present embodiment, the length L11 of the first shielding part 21a in the Y direction and the length L12 of the second shielding part 22a in the Y direction are It is characterized by being shorter than the length L01 in the Y direction. Here, the length L11 in the Y direction of the first shielding part 21a is the length of the first shielding part 21a in the direction perpendicular to the linear direction of inspection light (the left-right direction in FIG. 1). The length L12 of the second shielding part 22a in the Y direction is the length of the second shielding part 22a in the direction perpendicular to the linear direction of inspection light (the left-right direction in FIG. 1). Further, the length L01 in the Y direction of the light projecting device 16 is a direction perpendicular to the linear direction of the inspection light because the linear direction of the light projecting device 16 is the X direction (left and right direction in the drawing of FIG. 1). Length. As described above, in this embodiment, the “length in the direction perpendicular to the linear direction of the light projecting device 16” described in the claims is the case 18 as shown in FIG. This is the length of the inspection light opening 18a in the Y direction. Specifically, the lengths L11 and L12 are preferably 3 mm or more and 15 mm or less.

  The defect inspection apparatus 10 includes an inspection light shielding system 20 for preventing the inspection light from reaching the light receiving device 11 as a bright field, and the first shielding portion constituting the inspection light shielding system 20 in the Y direction. Since the lengths of 21a and the second shielding portion 22a are shorter than the width of the inspection light, the inspection light reaching the inspection target 15 is not interrupted more than necessary, and is caused by the defect D of the inspection target 15. The amount of scattered light increases, and the defect D can be detected with high accuracy.

  In FIG. 1, the length in the X direction of the first shielding portion 21 a and the length in the X direction of the second shielding portion 22 a are described as being equal for convenience. In the linear direction, there is no problem as long as the inspection light does not reach the light receiving device 11 as a bright field. Moreover, in FIG. 1, although all the 1st shielding parts 21a are represented by the same magnitude | size, it is not necessary for all to be the same magnitude | size. The same applies to the second shielding part 21b, and it is not necessary that all the second shielding parts 21b have the same size. However, it is necessary that at least a part of the first shielding part 21a is shorter than the length in the direction perpendicular to the linear direction of the light projecting device 16, and a part of the second shielding part 22a is a light projecting device 16. It is necessary to be shorter than the length in the direction perpendicular to the linear direction.

  In addition, although it has been described that the shielding plate is manufactured by performing removal processing such as laser processing from a non-transparent plate-like member, the present invention is not limited to this. For example, the shielding plate can be constituted by a transparent plate-like member, and the shielding plate can be constituted by printing the first shielding portion 21a and the like with non-transparent ink.

(Second Embodiment)
FIG. 4 is an explanatory diagram of the inspection light shielding system 20 constituting the defect inspection apparatus 10 according to the second embodiment of the present invention. The XYZ coordinates in this embodiment are the same as the coordinates in the first embodiment. The inspection light shielding system 20 is configured to include two shielding plates (FIGS. (A) and (B)) shown on the left side in FIG. In the upper left figure (A), the inspected object side shielding plate 21 is described, and in the lower left figure (B), the light projecting device side shielding plate 22 is described. In the right figure (C), a part of the inspection light shielding system 20 has the inspected object side shielding plate 21 on the upper side (front side in FIG. 4), and the light projecting device side shielding plate 22 on the lower side. It is described in a state (in the back side in FIG. 4). 4 shows a surface perpendicular to the surface formed by the linear light source 17 constituting the light projecting device 16 and the sensor unit 12 constituting the light receiving device 11 described in the claims. It represents the state. Specifically, it is a diagram when the lower side of the shielding target side shielding plate 21 is viewed from the upper side on the paper surface of FIG.

  The difference between the defect inspection apparatus 10 according to the second embodiment and the defect inspection apparatus 10 according to the first embodiment is the shape of the shielding plate constituting the inspection light shielding system 20.

  The inspected object-side shielding plate 21 according to the present embodiment is provided with a long left and right space in the center of the top and bottom and the left and right in the plane of FIG. 4, and a parallelogram first shielding portion 21 a is formed in this space portion. They are arranged in an intermittent manner. The shape of the first shielding part 21a is all a parallelogram. The first shielding part 21a is fixed by a support piece 23 to the edge part of the inspected object-side shielding plate 21 provided vertically on the paper surface of FIG. Thus, by arrange | positioning so that the 1st shielding part 21a may be located in a line, a part of linear test | inspection light along the longitudinal direction of the to-be-tested object side shielding board 21 is interrupted | blocked intermittently.

  Since the 1st shielding part 21a is a parallelogram, it is formed from two sets of two parallel sides. The two parallel sides of the first set are sides extending in the linear direction of the inspection light, that is, the X direction (the left-right direction in FIG. 4). The two parallel sides of the second set are sides that are not perpendicular to the linear direction of the inspection light. This has a predetermined angle θ with the X direction. This angle θ is preferably 25 degrees or more and 65 degrees or less.

  Further, the light projecting device side shielding plate 22 according to the present embodiment is provided with a long space on the left and right in the center of the top and bottom and the left and right in the paper surface of FIG. The parallelogram-shaped second shielding portions 22a are arranged intermittently. All of the shapes of the second shielding portions 22a are parallelograms. The second shielding portion 22a is fixed to the edge portion of the light projecting device side shielding plate 22 provided vertically on the paper surface of FIG. Thus, by arrange | positioning so that the 2nd shielding part 22a may be located in a line, a part of linear test | inspection light along the longitudinal direction of the light projection apparatus side shielding board 22 is interrupted | blocked intermittently. Further, the width of the support piece 23 in the X direction is made narrower than the width of the shielding plate in the X direction, thereby suppressing the shielding of the inspection light at the portion where the support piece 23 is present.

  Since the 2nd shielding part 22a is a parallelogram like the 1st shielding part 21a, it is formed from two sets of 2 parallel sides. The two parallel sides of the first set are sides extending in the linear direction of the inspection light, that is, the X direction (the left-right direction in FIG. 4). The two parallel sides of the second set are sides that are not perpendicular to the linear direction of the inspection light. This has a predetermined angle θ with the X direction in the same manner as the first shielding part 21a. That is, it corresponds to two parallel sides of the first shielding part 21a, which is not perpendicular to the linear direction of the inspection light, and two parallel sides of the second shielding part 22b. The sides that are not perpendicular to the linear direction of the inspection light are parallel to each other. The angle θ of the second shielding part 22a is also preferably 25 degrees or more and 65 degrees or less.

  The difference between the inspected object side shielding plate 21 and the light projecting apparatus side shielding plate 22 is that the position of the first shielding part 21a with respect to the entire inspected object side shielding plate 21 and the first with respect to the entire light projecting apparatus side shielding plate 22 are the same. 2 is the position of the shield 22a. Due to the difference in position, the inspection light from the light projecting device 16 does not reach the light receiving device 11 as a bright field.

  As in the first embodiment, when the first shielding portion 21a and the second shielding portion 22a are rectangular, that is, when the shielding plate has an end perpendicular to the X direction, the end perpendicular to the X direction. The disturbance light generated in the above is relatively incident on the sensor unit 12 of the light receiving device 11. The sensor unit 12 of the light receiving device 11 is arranged so as to be short in the X-axis direction. However, disturbance light generated at the end perpendicular to the X direction can be swung left and right (for example, left and right in the drawing of FIG. 3). This is because it proceeds in the Z direction (for example, upward in the plane of FIG. 3) and reaches the sensor unit 12.

  On the other hand, in this embodiment, the shielding part has two parallel sides that are not perpendicular to the X direction. The disturbance light generated at the end portion constituting this side swings to the left or right (for example, left and right in the drawing of FIG. 3) when traveling in the Z direction (for example, upward in the drawing of FIG. 3). It can suppress reaching.

  In FIG. 4, the length in the X direction of the first shielding portion 21 a and the length in the X direction of the second shielding portion 22 a are described equally for convenience. In the linear direction, there is no problem as long as the inspection light does not reach the light receiving device 11 as a bright field.

(Third embodiment)
In FIG. 5, the side view of the defect inspection apparatus 10 which concerns on 3rd Embodiment of this invention is shown. The XYZ coordinates in this embodiment are the same as the coordinates in the first embodiment. A thick two-dot chain line G1 is a straight line connecting the Y-direction end of the inspection light opening 18a of the light projecting device 16 and the focal position of the lens 13 on the inspection target 15, and a thick broken line G2 is A straight line connecting the Y-direction end of the first shielding part 21a and the focal point of the lens 13 on the inspection object 15. The difference between the defect inspection apparatus 10 according to the third embodiment and the defect inspection apparatus 10 according to the first embodiment is that an auxiliary shielding plate 24 is provided between the inspection target side shielding plate 21 and the inspection target 15. This is the point. For ease of understanding, the description of the upper and lower positions of the first shielding part 21a is changed in FIG.

  The two auxiliary shielding plates 24 are arranged in the Y direction so as to have an opening 24a that is long in the X direction. The length of the opening 24a in the Y direction is such a length that does not block the inspection light irradiated to the focal position of the lens 13 on the inspection target 15, and specifically, the auxiliary shielding plate 24 is provided. In the position of the existing Z coordinate, it is preferable to make it longer than the interval between the thick two-dot chain lines G1. Furthermore, it is more preferable that it is shorter than the interval of the broken line K and longer than the interval of the thick two-dot chain line G1.

  By providing the auxiliary shielding plate 24 between the inspected object side shielding plate 21 and the inspected subject 15, it is possible to suppress the amount of inspection light from becoming too large, and the image level increases unexpectedly. Thus, it is possible to prevent the contrast of the defect D from being lowered.

(Fourth embodiment)
In FIG. 6, the side view of the defect inspection apparatus 10 which concerns on 4th Embodiment of this invention is shown. In the present embodiment, the linear direction of the inspection light, that is, the depth direction on the paper surface of FIG. 6 is the X direction, and the traveling direction of the inspection target 15 that is the direction perpendicular to the linear direction of the inspection light, that is, the paper surface of FIG. The left-right direction is the Y direction, and the direction perpendicular to the flat surface of the inspection object 15, that is, the up-down direction on the paper surface of FIG. The difference between the defect inspection apparatus 10 according to the fourth embodiment and the defect inspection apparatus 10 according to the first embodiment is that the inspection light received by the light receiving device 11 is reflected by the surface of the inspection target 15. It is. For this reason, in the defect inspection apparatus 10 according to the present embodiment, the light projecting device 16 and the light receiving device 11 are arranged on one side of the inspection target 15. With such a configuration, it is possible to inspect the defect D even if the inspection target 15 does not transmit inspection light.

(Fifth embodiment)
In FIG. 7, explanatory drawing of the inspection light shielding system 20 which comprises the defect inspection apparatus 10 which concerns on 5th Embodiment of this invention is shown. The XYZ coordinates in this embodiment are the same as the coordinates in the first embodiment. The inspection light shielding system 20 is configured to include two shielding plates (FIGS. (A) and (B)) shown on the left side in FIG. In the upper left figure (A), the inspected object side shielding plate 21 is described, and in the lower left figure (B), the light projecting device side shielding plate 22 is described. In the right figure (C), a part of the inspection light shielding system 20 has the inspected object side shielding plate 21 on the upper side (front side in FIG. 7), and the light projecting device side shielding plate 22 on the lower side. It is described in a state of being on the side (the back side in FIG. 7). 7 shows a surface perpendicular to the surface formed by the linear light source 17 constituting the light projecting device 16 and the sensor unit 12 constituting the light receiving device 11 described in the claims. It represents the state. Specifically, it is a diagram when the lower side of the shielding target side shielding plate 21 is viewed from the upper side on the paper surface of FIG.

  The difference between the defect inspection apparatus 10 according to the fifth embodiment and the defect inspection apparatus 10 according to the first embodiment is the shape of the shielding plate constituting the inspection light shielding system 20. In the present embodiment, all of the first shielding portions 21a have the same shape. Moreover, all of the 2nd shielding part 22a is the same shape. The length of the second shielding portion 22a in the Y direction, that is, the length in the direction perpendicular to the linear direction of the inspection light is perpendicular to the length of the first shielding portion 21a in the Y direction, that is, the linear direction of the inspection light. It is longer than the length in any direction. In addition, when there are several kinds of lengths in the Y direction of the first shielding part 21a and there are several kinds of lengths in the Y direction of the second shielding part 22a, the length of the second shielding part 22a in the Y direction. The shortest of the lengths is longer than the longest of the lengths of the first shielding portions 21a.

  In the direction perpendicular to the linear direction of the inspection light, the length of the second shielding portion 22a close to the light projecting device 16 is longer than the length of the first shielding portion 21a close to the inspection target 15, so that the light receiving device 11 Unnecessary light entering the lens 13 constituting the lens is reduced, and deterioration in inspection accuracy due to irregular reflection inside the lens 13 can be suppressed.

DESCRIPTION OF SYMBOLS 10 Defect inspection apparatus 11 Light receiving apparatus 15 Inspected object 16 Light projection apparatus 20 Inspection light shielding system 21 Inspected object side shielding board 21a 1st shielding part 22 Light projection apparatus side shielding board 22a 2nd shielding part 24 Auxiliary shielding board

Claims (4)

An apparatus for inspecting a defect to be inspected having a flat surface,
A line light source projector that emits inspection light toward the inspection target; and
A light receiving device that receives the inspection light from the light projecting device via the inspection object, and
An inspection light shielding system for preventing the inspection light from reaching the light receiving device as a bright field is provided between the object to be inspected and the light projecting device,
The inspection light shielding system includes:
The inspection target side shielding plate capable of intermittently shielding a part of the linear inspection light by arranging the first shielding parts in the linear direction of the inspection light,
A light projecting device side shielding plate capable of intermittently shielding a part of the linear inspection light by arranging the second shielding parts in a linear direction of the inspection light; and
In a plane perpendicular to the surface formed by the light projecting device and the light receiving device,
The length of a part of the first shielding part or the part of the second shielding part in a direction perpendicular to the linear direction of the inspection light is longer than a length in a direction perpendicular to the linear direction of the light projecting device. Too short,
A defect inspection apparatus characterized by that. All of the first shield and all of the second shield are
In a plane perpendicular to the surface formed by the light projecting device and the light receiving device, it has a parallelogram shape,
The parallelogram is
Two sides parallel to the linear direction of the inspection light;
Formed from two parallel sides that are not perpendicular to the linear direction of the inspection light,
The defect inspection apparatus according to claim 1. Between the inspection object side shielding plate and the inspection object,
An auxiliary shielding plate is provided,
The defect inspection apparatus according to claim 1, wherein The shortest of the lengths of the second shielding portions in the direction perpendicular to the linear direction of the inspection light is:
Longer than the longest length of the first shielding portion in the direction perpendicular to the linear direction of the inspection light,
The defect inspection apparatus according to any one of claims 1 to 3.

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